Ultrafine-grained β-type titanium alloy with nonlinear elasticity and high ductility.

Although stress-induced martensitic transformation accelerates grain refinement during plastic deformation, it results in serious damage to recoverable elasticity and ductility of severely cold-rolled multifunctional titanium alloys. Here, large-scale nonlinear elasticity and high ductility were achieved simultaneously in an ultrafine-grained Ti–Nb–Zr–Sn alloy by severe warm rolling at 473 K to suppress the martensitic transformation from the β to the α″ phase. These results suggest that high strength can be attained in nonlinear elastic titanium alloys by improving the stability of the β phase with body-centered-cubic crystal structure through both composition design and grain refinement. [ABSTRACT FROM AUTHOR]