Observation of the omega phase particles in Ti15Mo alloy by electron microscopy

• Published in: Materials letters 2022-02, Vol.309, p.131376, Article 131376
• Main Authors: Bartha, Kristína, Stráský, Josef, Veverková, Anna, Veselý, Jozef, Janeček, Miloš
• Format: Article
• Language: English
• Subjects: Aging (metallurgy); Electron microscopes; Grain boundaries; Ion beams; Materials science; Metastable β titanium alloys; Scanning electron microscope; Scanning electron microscopy; Titanium alloys; Titanium base alloys; Transmission electron microscope; α lamellae; ω families; ω phase
• ISSN: 0167-577X; 1873-4979
• DOI: 10.1016/j.matlet.2021.131376

•Scanning electron microscopy (SEM) is capable of imaging ω phase particles.•β, ω, and α phases are present in Ti15Mo alloy after ageing at 500 °C/16 h.•Two ω families can be observed simultaneously by TEM.•Thin α laths with the thickness not exceeding 100 nm were also observed. High resolution scanning electron microscopy (SEM) is capable of imaging ω phase particles. The SEM observation of Ti15Mo metastable β titanium alloy after ageing at 500 °C for 16 h revealed that the material contains coarse β grains surrounded by grain boundary α phase. Thin lamellae associated with α phase were observed in grains interior. Most importantly, small ellipsoidal particles with the size of ∼100 nm were observed due to chemical contrast. Sample for TEM observation was extracted using focused ion beam to prove that these particles belong to isothermal ω phase that evolves during annealing. In the addition, presence of different families of the ω phase in the material was observed by the combination of bright and dark field imaging. Finally, thin lamellae of the α phase in the vicinity of grain boundary were observed using TEM.