Non-equilibrium Ti-Fe bulk alloys with ultra-high strength and enhanced ductility

The high-strength and ductile hypo-, hyper- and eutectic Ti-Fe alloys were formed in the shape of the arc-melted ingots with the dimensions of about 25-40 mm in diameter and 10-15 mm in height. The structure of the samples consists of cubic Pm3̄m TiFe and BCC Im 3̄ m β-Ti supersaturated solid solution phase. The arc-melted hypereutectic Ti₆₅Fe₃₅ alloy has a dispersed structure consisting of the primary TiFe phase and submicron-size eutectic structure. This alloy exhibits excellent mechanical properties: a Young's modulus of 149 GPa, a high mechanical fracture strength of 2.2 GPa, a 0.2 % yield strength of 1.8 GPa and 6.7 % ductility. The hard round-shaped intermetallic TiFe phase and the supersaturated β-Ti solid solution result in a high strength of the Ti₆₅Fe₃₅ alloy which in addition has much higher ductility compared to that of the nanostructured or glassy alloys. The reasons for the high ductility of the hypereutectic alloy are discussed.