Crystallography of Bcc/T1/T2 three-phase microstructure in the directionally solidified Mo-Nb-Si-B alloy

Naoki Takata, Nobuaki Sekido, Masao Takeyama, John H. Perepezko

Research output: Chapter in Book/Report/Conference proceedingConference contribution

5 Citations (Scopus)


In the present study, the crystallographic features of bcc/T1/T2 three-phase microstructure in a directionally solidified Mo-32.2Nb-19.5Si-4.7B (at.%) alloy have been examined by electron back-scattering diffraction (EBSD) analysis. The alloy was directionally solidified using an optical floating zone (OFZ) furnace in a flowing Ar gas atmosphere at a constant growth rate of 10 mm/hour. The microstructure of the directionally solidified alloy is characterized by an elongated T2 phase surrounded by inclusions of bcc and T1 phases with an interwoven morphology. The T2 grains are faceted on the (001) planes and elongated along the [110] direction. The T2 phase has an orientation relationship of (001)t2//(01 l)bcc and [130]T2//[211]bcc with the bcc phase, whereas any particular orientation relationships of T1 phase with bcc and T2 phases have not been found. These crystallographic features of bcc/T1/T2 three-phase microstructure suggest that the primary T2 phase crystallizes and grows along the [110] direction in liquid phase, followed by nucleation of the bcc phase on the interface between T2 and liquid phases, resulting in bcc/T1 two-phase eutectic reaction surrounding the elongated T2 phase.

Original languageEnglish
Title of host publicationAdvanced Structural and Functional Intermetallic-Based Alloys
EditorsI. Baker, M. Heilmaier, K. Kishida, M. Mills, S. Miura
PublisherMaterials Research Society
Number of pages6
ISBN (Electronic)9781510806344
Publication statusPublished - 2015
Externally publishedYes
Event2014 MRS Fall Meeting - Boston, United States
Duration: 2014 Nov 302014 Dec 5

Publication series

NameMaterials Research Society Symposium Proceedings
ISSN (Print)0272-9172


Other2014 MRS Fall Meeting
Country/TerritoryUnited States

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


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