Investigation of glass-forming ability,deformation and corrosion behavior of Ni-free Ti-based BMG alloys designed for application as dental implants

We developed new Ti-based bulk metallic glassy (BMG) alloys in Ti–Zr–Pd–Cu–Sn system without Ni element for application as biomaterials. These BMG alloys have a high potential to be applied as metallic biomaterials in various forms, such as melt-spun ribbons and cylindrical rods with a diameter of 4 mm. We also investigated of new Ti-based BMG alloys with higher glass-forming ability (GFA) for medical market as dental implants. These Ti-based BMG alloys do not contain Ni, Al and Be elements which are well known to be harmful for human body. In particular, a rod sample of the Ti_44.1Zr_9.8Pd_9.8Cu_30.38Sn_3.92Nb₂ BMG alloy with a diameter of 3 mm produced by copper mold casting exhibits a compressive strength of 1990 MPa and a Young's modulus of 99 GPa. In addition, the Ti_44.1Zr_9.8Pd_9.8Cu_30.38Sn_3.92Nb₂ BMG shows a large supercooled liquid region of 62 K and a reduced glass-transition temperature, T_rg( = T_g / T_m) of 0.61. The high thermal stability of the supercooled liquid allowed the fabrication of cylindrical rod specimens up to 5 mm in diameter. Thus the studied alloy exhibits high glass-forming ability (GFA) and a large size enough to be used for dental implants. The Ti_44.1Zr_9.8Pd_9.8Cu_30.38Sn_3.92Nb₂ BMG alloy also has a high corrosion resistance and is passivated at the lower passive current density of approximately 10^? 2 A m^? 2, 10^? 3 A m^? 2 and 10^? 2 A m^? 2, in 1 mass% lactic acid, PBS (phosphate-buffered saline without calcium and magnesium salts solution) and HBSS (Hank's balance salt solution without calcium, magnesium and phenol red), respectively, at 310 K, which are lower than those of pure Titanium and Ti–6Al–4V alloy.