Abstract: A high strength, high ductility titanium alloy comprising O, N and Fe as strengthening elements and the balance substantially Ti, the contents of the strengthening elements satisfying the following relationships (1) to (3):(1) from 0.9 to 2.3% by weight of Fe,(2) up to 0.05% by weight of N, and(3) an oxygen equivalent value Q, which is defined by the formula mentioned below, of 0.34 to 1.00Q=[O]+2.77[N]+0.1[Fe]wherein [O] is an oxygen content (% by weight), [N] is a nitrogen content (% by weight) and [Fe] is an iron content (% by weight), the titanium alloy having a tensile strength of at least 700 MPa and an elongation of at least 15%. Part of Fe may be replaced with Cr and/or Ni. Fe, Cr and Ni may be introduced from a carbon steel or stainless steel, or they may be introduced from sponge titanium containing these elements.

Abstract: A method of manufacturing a rolled titanium alloy sheet comprises breaking down an .alpha. or .alpha.+.beta. titanium alloy ingot into a slab, working the slab in sequential stages of(A) cross rolling the slab in the .alpha.+.beta. region under a condition of a reduction ratio of at least 1.2 and a cross rolling ratio of 0.6 to 1.4,(B) annealing the workpiece for recrystallization at a temperature 20.degree. to 100.degree. C., preferably 20.degree. to 70.degree. C., below the .beta.-transus of the alloy, and(C) further cross rolling it in the .alpha.+.beta. region under a condition of a reduction ratio of at least 1.6 and a cross rolling ratio of 0.6 to 1.4,and thereafter heat treating the rolled workpiece for annealing, solution treatment and aging or the like, depending on the intended use of the product. The method may include an additional stage (D) of repeating stages (B) and (C) at least once each. The ingot breakdown is preferably carried out by forging or rolling at a temperature of the two-phase .