New high strength and high toughness titanium alloy with 1200 MPa

Ti usage in airplane is obviously increasing, the requirements for Ti-alloys are changing to high strength and high toughness with the changing of airplane design concept. In order to design a new Ti-alloy with tensile strength over 1200 MPa and fracture toughness over 65 MPa·m^1/2, the following factors should be paid attention to: Mo equivalent, effects of alloying elements and microstructures on strength and toughness of α phase and β phase. A new Ti alloy named as Ti-5321 was designed, which is a rich-β alloy. Bars were forged from 30 kg and 500 kg ingots. With the ideal microstructure, the bars of the new alloy have a good match between strength and toughness, that is, tensile strength over 1200 MPa, elongation over 8% and fracture toughness over 65 MPa·m^1/2. Compared with the TC21, Ti-5553 and Ti-55531 alloy, the new alloy possesses obvious advantages.