TITANIUM ALLOY MATERIAL WITH HIGH TOUGHNESS AND MANUFACTURING METHOD THEREFOR

PROBLEM TO BE SOLVED: To provide a titanium alloy which develops an unprecedented high level of strength and excellent characteristics in fracture toughness, and is superior in fatigue characteristics, without employing a new heat treatment process, and provide a manufacturing method therefor. SOLUTION: This method for manufacturing a titanium alloy with high toughness, includes employing the titanium alloy material which is characterized by having a microstructure of an α+β type, a volume fraction of a pro-eutectoid α-phase of 10% or more but 90% or less, an average crystal particle diameter of the pro-eutectoid α-phase of 2 μm or more but 10 μm or less, and the volume fracture of the pro-eutectoid α-phase having an aspect ratio of 4 or more, of 10% or more. The method preferably employs the titanium alloy material particularly having a chemical composition of, by mass%, 4.0-5.0% Al, 2.5-3.5% V, 1.5-2.5% Fe, 1.5-2.5% Mo, and the balance substantially Ti.