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 beta to the alpha '' phase. These results suggest that high strength can be attained in nonlinear elastic titanium alloys by improving the stability of the beta phase with body-centered-cubic crystal structure through both composition design and grain refinement. (C) 2008 American Institute of Physics.