Effects of Mn Addition on Tensile and Charpy Impact Properties in Austenitic Fe-Mn-C-Al-Based Steels for Cryogenic Applications

Junghoon Lee, Seok S Sohn, Seokmin Hong, Byeong Chan Suh, Sung Kyu Kim, Byeong Joo Lee, Nack J. Kim, Sunghak Lee

Research output: Contribution to journalArticle

16 Citations (Scopus)

Abstract

Effects of Mn addition (17, 19, and 22 wt pct) on tensile and Charpy impact properties in three austenitic Fe-Mn-C-Al-based steels were investigated at room and cryogenic temperatures in relation with deformation mechanisms. Tensile strength and elongation were not varied much with Mn content at room temperature, but abruptly decreased with decreasing Mn content at 77 K (−196 °C). Charpy impact energies at 273 K (0 °C) were higher than 200 J in the three steels, but rapidly dropped to 44 J at 77 K (−196 °C) in the 17Mn steel, while they were higher than 120 J in the 19Mn and 22Mn steels. Although the cryogenic-temperature stacking fault energies (SFEs) were lower by 30 to 50 pct than the room-temperature SFEs, the SFE of the 22Mn steel was situated in the TWinning-induced plasticity regime. In the 17Mn and 19Mn steels, however, α′-martensites were formed by the TRansformation-induced plasticity mechanism because of the low SFEs. EBSD analyses along with interrupted tensile tests at cryogenic temperature showed that the austenite was sufficiently deformed in the 19Mn steel even after the formation of α′-martensite, thereby leading to the high impact energy over 120 J.

Original languageEnglish
Pages (from-to)5419-5430
Number of pages12
JournalMetallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
Volume45
Issue number12
DOIs
Publication statusPublished - 2014 Jan 1
Externally publishedYes

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Metals and Alloys

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