Microstructural change during isothermal aging in high manganese austenitic steels

Yoshinori Ono, Toshihiro Tsuchiyama, Setsuo Takaki

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7 Citations (Scopus)


Microstructural change during isothermal aging has been investigated 13%Mn-0.9%C and 22%Mn-0.6%C steels by means of optical and electron microscopy and X-ray diffractometry. High manganese austenitic steels undergo three kinds of reactions during isothermal aging; (1) grain boundary precipitation of carbide, (2) precipitation of platelet carbide within austenite (γ) grains and (3) formation of lamellar structure through eutectoid transformation (γ→ferrite (α)+carbide). In 13%Mn-0.9%C steel, all of the reactions occur and the carbide concerning the reactions is M3C in any case. On the other hand, in 22%Mn-0.6%C steel, only two of them occur; grain boundary precipitation of M23C6 carbide (not M3C) and the eutectoid transformation (γYLDα+M3C). Besides, both of the two reactions in 22%Mn-0.6%C steel were effectively suppressed due to the chemical composition; high Mn and low C content. Eutectoid transformation proceeds by being supplied carbon from untransformed γ, so that this results in the shortage of carbon in untransformed γ during isothermal aging and the γ phase undergoes γ→ε (hcp) martensitic transformation on the following cooling.

Original languageEnglish
Pages (from-to)309-314
Number of pages6
JournalTetsu-To-Hagane/Journal of the Iron and Steel Institute of Japan
Issue number4
Publication statusPublished - 1998

All Science Journal Classification (ASJC) codes

  • Condensed Matter Physics
  • Physical and Theoretical Chemistry
  • Metals and Alloys
  • Materials Chemistry

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