Characterization of a previously unidentified ordered orthorhombic metastable phase in Ti-5Al-5Mo-5V-3Cr

SCRIPTA MATERIALIA

卷:113

Article

Zheng, Yufeng ; Williams, Robert E. A. ; Fraser, Hamish L.

关键词: Titanium alloys;    Phase transformations;    Ordering;    High-resolution electron microscopy;   

DOI  :  10.1016/j.scriptamat.2015.10.037

来源: Elsevier

【 摘 要 】

A previously unidentified, nanometer scale ordered precipitate has been characterized in the metastable beta titanium alloy Ti-5Al-5Mo-5V-3Cr (Ti-5553) using conventional transmission electron microscopy (TEM) and high-angle annular dark field (HAADF) high-resolution scanning transmission electron microscopy (HRSTEM). The phase, termed O, is metastable, the ordering transformation occurring over an intermediate temperature range (e.g., 375 degrees C), and this ordered face centered orthorhombic precipitate may be observed co-existing with isothermal omega and alpha phases in the alloy. It is also noted that this transient phase may provide the diffracted intensities observed from another phase, identified tentatively in the literature as orthorhombic martensite, alpha [1]. (C) 2015 Elsevier Ltd. All rights reserved.

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