The effect of alloy composition on instabilities in the β phase of titanium alloys

• Published in: Scripta materialia Vol. 116; pp. 49 - 52
• Main Authors: Zheng, Yufeng, Williams, Robert E.A., Nag, Soumya, Banerjee, Rajarshi, Fraser, Hamish L., Banerjee, Dipankar
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 15.04.2016
• Subjects: Composition effects; High-resolution electron microscopy; Martensite; Nanostructure; Niobium; Phase transformations; Phonons; Precipitates; Precipitation; Quenching (cooling); Stability; Titanium alloys; Titanium base alloys; Zirconium; Titanium alloys; Phase transformations; Martensite; High-resolution electron microscopy
• ISSN: 1359-6462; 1872-8456
• DOI: 10.1016/j.scriptamat.2016.01.024

A metastable nano-scale disordered precipitate with orthorhombic symmetry has been identified using high resolution scanning transmission electron microscopy. The phase, termed O′, is metastable, formed by a shuffle mechanism involving a 110<11̅0> transverse phonon wave in samples of Ti–26Nb–2Zr (at.%) quenched from the β phase. The addition of 2% Zr to Ti–26Nb appears to suppress significantly the stability of both the 112̅ shear and 2/3 longitudinal phonon wave but promotes the 110<11̅0> transverse shuffle. This results in the nano-size O′ phase being homogeneously formed in the parent β phase matrix rather than the massive α″ phase. [Display omitted]