ω precipitation: Deformation regulator in metastable titanium alloys

• Published in: Materials science & engineering. A, Structural materials : properties, microstructure and processing Vol. 772; p. 138687
• Main Authors: Xiao, J.F., Nie, Z.H., Ma, Z.W., Liu, G.F., Hao, F., Tan, C.W.
• Format: Journal Article
• Language: English
• Published: Lausanne Elsevier B.V 20.01.2020; Elsevier BV
• Subjects: Binary alloys; Deformation mechanism; Deformation mechanisms; Grain orientation; Heat treatment; Metastable titanium alloy; Modulated structure; Phase stability; Titanium alloys; Titanium base alloys; Twinning; ω precipitation; Modulated structure; Metastable titanium alloy; Phase stability; ω precipitation; Deformation mechanism
• ISSN: 0921-5093; 1873-4936
• DOI: 10.1016/j.msea.2019.138687

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} 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.