Rolling Texture of α"-Phase in Ti-22mol%Nb-3mol%Al Biomedical Shape Memory Alloy

Abstract

Rolling texture of α"(C-orthorhombic) martensite phase in Ti-22mol%Nb-3mol%Al β-titanium based shape memory alloy was examined using X-ray pole figure measurement. The alloy was dual phase of α'' and β(bcc) at room temperature (RT) and was cold-rolled with reduction rates of 40%~99% at RT. Stress-induced martensitic transformation occurred during the rolling and then the material was fully transformed into martensite phase. Subscript α" and β indicate martensite and parent phase hereafter. The major texture was close to {411}α"<173>α" when the reduction rate was lower than 60%. This texture is a result of a preferential formation of specific variants which have a higher interaction with the macroscopic deformation. As the reduction rate was increased, ND moved toward {101}α" whereas RD was around <010>α" regardless of the reduction rate. {101}α"<010>α" texture was confirmed when the reduction rate was 99%.