ω precipitation: Deformation regulator in metastable titanium alloys

The deformation mechanism of a binary metastable titanium alloy Ti–15Mo that had been subjected to various heat treatment regimes was investigated in this work. Microstructures and diffuse streaks were revealed using electron back-scattered diffraction (EBSD) and transmission electron microscopy (TEM). The evolution of the deformation mechanisms were identified as being from primary and secondary {332} twinning → {332} twinning + {112} twinning → {332} twinning + {112} twinning + dislocation slips → dislocation slips with varying initial microstructures. The diffuse streaks corresponding to the soft-phonon shuffling along the {110}<110>_β direction were caused by the substitutional Mo atoms and their local strain fields. These nano-sized modulated structures were strongly influenced by phase stability and also proved to serve as a critical factor in deformation mechanisms of this material. Meanwhile, the preferential growth of a nano-sized modulated structure variant took place and was studied to highlight the relationship between loading direction and grain orientation.