Crystallographic features of the ν phase in the Mn-Si binary alloy system

Kei Nakayama, Shouhei Yabu, Takashi Mizuno, Yasumasa Koyama

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

Abstract

In the Mn-Si alloy system, there is the intermetallic-compound ν phase around Mn-18at.%Si. Its crystal structure called the ν structure has been reported to involve complex coordination polyhedra with coordination numbers (CN's) 12, 14, and others. To clarify whether one of these polyhedra can be identified as a structural unit or not in the ν structure, we have investigated the crystallographic features of the (R → R + ν) reaction in Mn-15at.%Si alloy samples by transmission electron microscopy. In Mn-15at.%Si samples obtained by cooling from the single R phase at a relatively fast cooling rate, metastable precipitates were found to be present in the R-structure matrix. Their notable feature is that each precipitate involves regions exhibiting characteristic electron diffraction patterns, which indicate the presence of metastable states, in addition to the initial amorphous and final ν states. Based on the careful analysis of these patterns, it was understood that the metastable states were directly associated with the formation of the ν structure, and that the formation started with the appearance of dodecagonal atomic columns. Because a dodecagonal column is characterized by a one-dimensional array of CN14 polyhedra, among the coordination polyhedra involved in the ν structure, a CN14 polyhedron can be identified as its structural unit.

Original languageEnglish
Title of host publicationTHERMEC 2013 Supplement
PublisherTrans Tech Publications
Pages525-530
Number of pages6
ISBN (Print)9783038350743
DOIs
Publication statusPublished - 2014
Event8th International Conference on Processing and Manufacturing of Advanced Materials: Processing, Fabrication, Properties, Applications, THERMEC 2013 - Las Vegas, NV, United States
Duration: 2013 Dec 22013 Dec 6

Publication series

NameAdvanced Materials Research
Volume922
ISSN (Print)1022-6680

Conference

Conference8th International Conference on Processing and Manufacturing of Advanced Materials: Processing, Fabrication, Properties, Applications, THERMEC 2013
CountryUnited States
CityLas Vegas, NV
Period13/12/213/12/6

Keywords

  • Coordination polyhedra
  • Dodecagonal atomic column
  • Intermetallic compound
  • Mn-Si alloy system
  • Transmission electron microscopy

ASJC Scopus subject areas

  • Engineering(all)

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  • Cite this

    Nakayama, K., Yabu, S., Mizuno, T., & Koyama, Y. (2014). Crystallographic features of the ν phase in the Mn-Si binary alloy system. In THERMEC 2013 Supplement (pp. 525-530). (Advanced Materials Research; Vol. 922). Trans Tech Publications. https://doi.org/10.4028/www.scientific.net/AMR.922.525