| Abstract Scope |
Twinning plays an important role during deformation in metastable beta titanium alloys. A number of different highly indexed twinning systems have been observed in metastable beta titanium alloys, including {10 9 3}<3 3 1>β and {332}<112>β deformation twins. Interestingly, a variety of nanoscale substructures have been characterized in different regions in these highly indexed deformation twins, such as martensitic alpha” phase, omega phase, and O’ phase. This work reports the investigation of nanoscale substructure formed in the cold-rolled Ti-Mo, Ti-Nb, and Ti-5Al-5Mo-5V-3Cr alloys using scanning electron microscopy, transmission electron microscopy, and aberration corrected scanning transmission electron microscopy. An orthorhombic alpha” layer is observed at {332} twin boundary, while an omega layer is characterized at {112} twin boundary. The microstructure evolution during subsequent aging has been studied using transmission electron microscopy and atom probe tomography. The role of pre-formed nanostructures during the microstructure evolution in these alloys will be introduced. |