α′ Martensite Ti-V-Sn alloys with low Young's modulus and high strength

Microstructures and mechanical properties of strength, ductility and Young's modulus were investigated using quenched and cold rolled Ti-V and Ti-V-Sn alloys consisting of α′ martensite. Young's modulus of both quenched and cold rolled (Ti-8 mass% V)-Sn alloys decreases with increasing Sn content, which is attributable to the lattice expansion by Sn addition. During cold rolling to a reduction of 86%, acicular α′ martensite structure in quenched Ti-8 mass% V and (Ti-8 mass% V)-4 mass% Sn changes into extremely fine dislocation cell-like structure with an average size of 60 nm, thereby increasing strength drastically. Sn addition to Ti-V alloys is effective for increasing ductility with keeping low Young's modulus and high strength. Thus, cold rolled α′ martensite Ti-V-Sn alloy is found to be attractive as a new type Ti alloy with low Young's modulus and high strength.