Structure and properties of cast binary Ti–Mo alloys

Structure and properties of a series of binary Ti–Mo alloys with molybdenum contents ranging from 6 to 20 wt% have been investigated. Experimental results indicated that crystal structure and morphology of the cast alloys were sensitive to their molybdenum contents. The hexagonal α′ phase c.p. Ti exhibited a feather-like morphology. When Mo content was 6 wt%, a fine, acicular martensitic structure of orthorhombic α″ phase was observed. When Mo content was 7.5 wt%, the entire alloy was dominated by the martensitic α″ structure. When Mo content was increased to 10 wt% or higher, the retained β phase became the only dominant phase. Among all Ti–Mo alloys, the α″ phase Ti–7.5Mo alloy had the lowest hardness. The bending strength of Ti–7.5Mo was similar to that of Ti–15Mo and Ti–13Nb–13Zr, and higher than c.p. Ti by nearly 60%. The bending modulus of the α″-dominated Ti–7.5Mo alloy was lower than that of Ti–15Mo by 22%, of Ti–6Al–4V by 47%, of Ti–13Nb–13Zr by 17%, and of c.p. Ti by 40%.