Influence of texture on the superelasticity and elastic modulus of Ti-20Nb-10Zr alloy

Abstract

A new Ti-20Nb-10Zr alloy with e/a of 4.2 was designed for biomaterials. The superelasticity (SE), elastic modulus and microstructure of this alloy with different cold rolling ratios (CRRs) and 1173 K/30min solution treatment (ST), CRR89.5 %-ST and CRR91 %-ST and CRR94.5 %-ST, were investigated by conventional and cyclic tensile tests and electron backscatter diffraction (EBSD). This alloy consisted of β phase only at room temperature after solution treatment at 1173 K for 30 min. The fracture strain of this alloy was greater than 40 %. EBSD observation showed that the recrystallization texture changed significantly with the increase of CRR from 89.5 % to 94.5 %. It was initially a weak {112}< 241 > texture, and then transformed into a strong {111}<112> texture and a weak {223}<341> texture, and finally formed a super strong {111}<110> texture. The formation of recrystallization texture depends on the mechanism of oriented nucleation or oriented growth. The CRR94.5 %-ST is equipped with high SE of 3 % and low elastic modulus of 50.5 GPa at the same time. The {111}<110> texture is not only beneficial to improve SE but also favorable to decrease elastic modulus. Thus, these results indicate that tailoring {111}<110> texture could be considered as promising technique for developing biomedical β titanium alloys with high superelasticity and low elastic modulus.