Orientation of austenite reverted from martensite in Fe-2Mn-1.5Si-0.3C alloy

Xianguang Zhang, Goro Miyamoto, Yuki Toji, Shoichi Nambu, Toshihiko Koseki, Tadashi Furuhara

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

The orientation of austenite (γ) reverted from lath martensite has been studied using electron backscatter diffraction (EBSD) in Fe-2%Mn-1.5%Si-0.3%C (mass%) alloy. Two morphologies of γ, acicular and globular, are formed during reversion. Nucleation sites for acicular γ are lath, block and sub-block boundaries, while those for globular γ are prior γ grain boundaries, as well as inside packets. Both acicular and globular γ hold a near Kurdjumov-Sachs (K-S) orientation relationship with at least one of its surrounding tempered martensite blocks. Most acicular γ have almost identical orientations with the prior γ, while only a part of acicular γ have a specific twin-related variant with the prior γ. Furthermore, grain boundary globular γ has almost identical orientations with the prior γ into which it does not grow. The formation of acicular and grain-boundary globular γ was attributed to strong variant selection during γ nucleation at lath, block and sub-block boundaries. On the other hand, orientation relationship analyses among intragranular globular γ, tempered martensite and cementite suggest that the nucleation of γ at cementite and tempered martensite interfaces causes weakening of the variant selection for the formation of intragranular globular γ.

Original languageEnglish
Pages (from-to)601-612
Number of pages12
JournalActa Materialia
Volume144
DOIs
Publication statusPublished - 2018 Feb 1

Keywords

  • Austenite reversion
  • Electron backscatter diffraction
  • Lath martensite
  • Orientation relationship
  • Variant selection

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Polymers and Plastics
  • Metals and Alloys

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