Design and fabrication of a (β+α″) dual-phase Ti-Nb-Sn alloy with linear deformation behavior for biomedical applications

In this study, a (β+α″) dual-phase Ti-33Nb-4Sn alloy was successfully fabricated by a designated severe cold rolling plus pre-deformation (CRP) treatment to display a linear deformation behavior. Upon CRP treatment, a high density of dislocation tangles and grain refinement were induced into the Ti-33Nb-4Sn alloy consisting mainly of α″ martensite as well as some retained β parent phase. Due to the retardation effect of dislocations and grain boundaries on martensitic transformation, the slight stress induced martensitic (SIM) transformation from β to α″ in CRP Ti-33Nb-4Sn alloy covered a wide stress range during loading, together with the linear elastic deformation behavior of β and α″ phases. In such a case, the (β+α″) dual-phase Ti-33Nb-4Sn alloy exhibited macroscopically linear deformation behavior before yielding. Our results might shed light on design and development of novel (β+α″) dual-phase Ti-based alloy with linear deformation behavior for biomedical applications.