LAUSR

Abstract The α phase precipitation of β →β’→α in the Ti–13Nb–13Zr alloy has been observed by transmission electron microscopy (TEM) and high resolution transmission electron microscopy (HRTEM). The images clearly show that the α phase nucleates at the β′ interface which has a rotation angle with the β matrix. The precipitation of α phase from the β′ phase experiences four steps, each step is similar to the twinning and the symmetric angle successively increases from 57° to 62°, 76° and finally to 90°. The crystallographic relationships between β and β’ were also discussed. This study provides guidance in the future for tailoring microstructure of titanium alloys.