Effect of Tempering on the Microstructure and Tensile Properties of a Martensitic Medium-Mn Lightweight Steel

Sukjin Lee, Seok Hyeon Kang, Jae Hoon Nam, Sang Min Lee, Jae Bok Seol, Young-Kook Lee

Research output: Contribution to journalArticle

Abstract

In the present study a Fe-8.8Mn-5.1Al-0.31C (wt pct) medium-Mn lightweight steel with martensitic matrix was newly designed, and the effect of tempering on its microstructure and tensile properties was investigated. When the medium-Mn lightweight steel specimen was quenched from annealing temperature of 1373 K (1100 °C), it revealed a triple-phase microstructure consisting of 64.6 pct fresh martensite, 20.2 pct ferrite, and 15.2 pct retained austenite. Tempering the as-quenched specimen at temperatures less than 573 K (300 °C) induced the precipitation of thin cementite or κ-carbide platelets in tempered martensite. With the increasing tempering temperature, the type of precipitate changed from cementite to κ-carbide, and thickening of platelets with the longer interspacing was observed by means of transmission electron microscopy and atom probe tomography. While the as-quenched specimen revealed high strain-hardening rate (SHR) and poor elongation (< 2 pct), tempered specimens exhibited moderate SHR and improved elongation (> 16.8 pct) mainly due to gradual transformation-induced plasticity in retained austenite stabilized by tempering. In particular, the 373 K (100 °C)-tempered specimen with tempered martensite embedded with thin cementite platelets revealed ultrahigh strengths (yield strength of 945 MPa and ultimate tensile strength of ~ 1.56 GPa) with moderate elongation of ~ 16.8 pct.

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tempering
Steel
tensile properties
Tempering
Tensile properties
cementite
Platelets
platelets
martensite
Martensite
steels
microstructure
Microstructure
austenite
carbides
Austenite
elongation
Carbides
Elongation
strain hardening

All Science Journal Classification (ASJC) codes

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

Cite this

@article{113b0bf0dda243feb1e4dba8d5a1661b,
title = "Effect of Tempering on the Microstructure and Tensile Properties of a Martensitic Medium-Mn Lightweight Steel",
abstract = "In the present study a Fe-8.8Mn-5.1Al-0.31C (wt pct) medium-Mn lightweight steel with martensitic matrix was newly designed, and the effect of tempering on its microstructure and tensile properties was investigated. When the medium-Mn lightweight steel specimen was quenched from annealing temperature of 1373 K (1100 °C), it revealed a triple-phase microstructure consisting of 64.6 pct fresh martensite, 20.2 pct ferrite, and 15.2 pct retained austenite. Tempering the as-quenched specimen at temperatures less than 573 K (300 °C) induced the precipitation of thin cementite or κ-carbide platelets in tempered martensite. With the increasing tempering temperature, the type of precipitate changed from cementite to κ-carbide, and thickening of platelets with the longer interspacing was observed by means of transmission electron microscopy and atom probe tomography. While the as-quenched specimen revealed high strain-hardening rate (SHR) and poor elongation (< 2 pct), tempered specimens exhibited moderate SHR and improved elongation (> 16.8 pct) mainly due to gradual transformation-induced plasticity in retained austenite stabilized by tempering. In particular, the 373 K (100 °C)-tempered specimen with tempered martensite embedded with thin cementite platelets revealed ultrahigh strengths (yield strength of 945 MPa and ultimate tensile strength of ~ 1.56 GPa) with moderate elongation of ~ 16.8 pct.",
author = "Sukjin Lee and Kang, {Seok Hyeon} and Nam, {Jae Hoon} and Lee, {Sang Min} and Seol, {Jae Bok} and Young-Kook Lee",
year = "2019",
month = "1",
day = "1",
doi = "10.1007/s11661-019-05190-4",
language = "English",
journal = "Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science",
issn = "1073-5623",
publisher = "Springer Boston",

}

Effect of Tempering on the Microstructure and Tensile Properties of a Martensitic Medium-Mn Lightweight Steel. / Lee, Sukjin; Kang, Seok Hyeon; Nam, Jae Hoon; Lee, Sang Min; Seol, Jae Bok; Lee, Young-Kook.

In: Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science, 01.01.2019.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Effect of Tempering on the Microstructure and Tensile Properties of a Martensitic Medium-Mn Lightweight Steel

AU - Lee, Sukjin

AU - Kang, Seok Hyeon

AU - Nam, Jae Hoon

AU - Lee, Sang Min

AU - Seol, Jae Bok

AU - Lee, Young-Kook

PY - 2019/1/1

Y1 - 2019/1/1

N2 - In the present study a Fe-8.8Mn-5.1Al-0.31C (wt pct) medium-Mn lightweight steel with martensitic matrix was newly designed, and the effect of tempering on its microstructure and tensile properties was investigated. When the medium-Mn lightweight steel specimen was quenched from annealing temperature of 1373 K (1100 °C), it revealed a triple-phase microstructure consisting of 64.6 pct fresh martensite, 20.2 pct ferrite, and 15.2 pct retained austenite. Tempering the as-quenched specimen at temperatures less than 573 K (300 °C) induced the precipitation of thin cementite or κ-carbide platelets in tempered martensite. With the increasing tempering temperature, the type of precipitate changed from cementite to κ-carbide, and thickening of platelets with the longer interspacing was observed by means of transmission electron microscopy and atom probe tomography. While the as-quenched specimen revealed high strain-hardening rate (SHR) and poor elongation (< 2 pct), tempered specimens exhibited moderate SHR and improved elongation (> 16.8 pct) mainly due to gradual transformation-induced plasticity in retained austenite stabilized by tempering. In particular, the 373 K (100 °C)-tempered specimen with tempered martensite embedded with thin cementite platelets revealed ultrahigh strengths (yield strength of 945 MPa and ultimate tensile strength of ~ 1.56 GPa) with moderate elongation of ~ 16.8 pct.

AB - In the present study a Fe-8.8Mn-5.1Al-0.31C (wt pct) medium-Mn lightweight steel with martensitic matrix was newly designed, and the effect of tempering on its microstructure and tensile properties was investigated. When the medium-Mn lightweight steel specimen was quenched from annealing temperature of 1373 K (1100 °C), it revealed a triple-phase microstructure consisting of 64.6 pct fresh martensite, 20.2 pct ferrite, and 15.2 pct retained austenite. Tempering the as-quenched specimen at temperatures less than 573 K (300 °C) induced the precipitation of thin cementite or κ-carbide platelets in tempered martensite. With the increasing tempering temperature, the type of precipitate changed from cementite to κ-carbide, and thickening of platelets with the longer interspacing was observed by means of transmission electron microscopy and atom probe tomography. While the as-quenched specimen revealed high strain-hardening rate (SHR) and poor elongation (< 2 pct), tempered specimens exhibited moderate SHR and improved elongation (> 16.8 pct) mainly due to gradual transformation-induced plasticity in retained austenite stabilized by tempering. In particular, the 373 K (100 °C)-tempered specimen with tempered martensite embedded with thin cementite platelets revealed ultrahigh strengths (yield strength of 945 MPa and ultimate tensile strength of ~ 1.56 GPa) with moderate elongation of ~ 16.8 pct.

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U2 - 10.1007/s11661-019-05190-4

DO - 10.1007/s11661-019-05190-4

M3 - Article

AN - SCOPUS:85063191399

JO - Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science

JF - Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science

SN - 1073-5623

ER -