Austenite stabilization kinetics in early stages of austempering treatment in TRIP-aided steel using in-situ neutron diffraction technique

Yutao Zhou; Tomohiko Hojo; Amane Kitahara; Yusuke Onuki; Shigeo Sato; Motomichi Koyama; Eiji Akiyama

doi:10.1016/j.mtla.2022.101317

Austenite stabilization kinetics in early stages of austempering treatment in TRIP-aided steel using in-situ neutron diffraction technique

Yutao Zhou, Tomohiko Hojo, Amane Kitahara, Yusuke Onuki, Shigeo Sato, Motomichi Koyama, Eiji Akiyama

Materials Design Division

Research output: Contribution to journal › Article › peer-review

Abstract

The transformation and stabilization behaviors of the austenite (γ) phase during bainite transformation in the early stages of austempering treatment of low-alloy transformation-induced plasticity-aided bainitic ferrite (TBF) steel were investigated by in-situ neutron diffraction measurement and microstructure observation. Neutron diffraction peak profile analysis with a short time range resolution showed the changes in the phase fractions and the lattice constants of the α and γ phases in TBF steel during rapid cooling and austempering treatment. The γ phase with a low carbon concentration (γ_(low-C)-Fe) immediately disappeared before the austempering time of 300 s. This indicates a remarkable increase in the lattice constant of the γ with a high carbon concentration (γ_(high-C)-Fe) because of the bainite transformation of γ_(low-C)-Fe and carbon partitioning to γ_(high-C)-Fe. When the austempering time increased from 300 s to 3600 s, the volume fraction of γ_(high-C)-Fe monotonically decreased and the lattice constant was hardly changed.

Original language	English
Article number	101317
Journal	Materialia
Volume	21
DOIs	https://doi.org/10.1016/j.mtla.2022.101317
Publication status	Published - 2022 Mar

Keywords

Austempering treatment
Carbon partitioning
In-situ neutron diffraction
Phase transformation
Retained austenite
TRIP-aided steel

ASJC Scopus subject areas

Materials Science(all)

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10.1016/j.mtla.2022.101317

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title = "Austenite stabilization kinetics in early stages of austempering treatment in TRIP-aided steel using in-situ neutron diffraction technique",

abstract = "The transformation and stabilization behaviors of the austenite (γ) phase during bainite transformation in the early stages of austempering treatment of low-alloy transformation-induced plasticity-aided bainitic ferrite (TBF) steel were investigated by in-situ neutron diffraction measurement and microstructure observation. Neutron diffraction peak profile analysis with a short time range resolution showed the changes in the phase fractions and the lattice constants of the α and γ phases in TBF steel during rapid cooling and austempering treatment. The γ phase with a low carbon concentration (γ(low-C)-Fe) immediately disappeared before the austempering time of 300 s. This indicates a remarkable increase in the lattice constant of the γ with a high carbon concentration (γ(high-C)-Fe) because of the bainite transformation of γ(low-C)-Fe and carbon partitioning to γ(high-C)-Fe. When the austempering time increased from 300 s to 3600 s, the volume fraction of γ(high-C)-Fe monotonically decreased and the lattice constant was hardly changed.",

keywords = "Austempering treatment, Carbon partitioning, In-situ neutron diffraction, Phase transformation, Retained austenite, TRIP-aided steel",

author = "Yutao Zhou and Tomohiko Hojo and Amane Kitahara and Yusuke Onuki and Shigeo Sato and Motomichi Koyama and Eiji Akiyama",

note = "Funding Information: The neutron diffraction experiments were conducted at the Materials and Life Science Experimental Facility of J-PARC under proposal No. 2018AM0016. Yutao Zhou is grateful to the China Scholarship Council for the financial support. Funding Information: The neutron diffraction experiments were conducted at the Materials and Life Science Experimental Facility of J-PARC under proposal No. 2018AM0016. Yutao Zhou is grateful to the China Scholarship Council for the financial support. Publisher Copyright: {\textcopyright} 2022 Acta Materialia Inc.",

year = "2022",

month = mar,

doi = "10.1016/j.mtla.2022.101317",

language = "English",

volume = "21",

journal = "Materialia",

issn = "2589-1529",

publisher = "Elsevier BV",

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TY - JOUR

T1 - Austenite stabilization kinetics in early stages of austempering treatment in TRIP-aided steel using in-situ neutron diffraction technique

AU - Zhou, Yutao

AU - Hojo, Tomohiko

AU - Kitahara, Amane

AU - Onuki, Yusuke

AU - Sato, Shigeo

AU - Koyama, Motomichi

AU - Akiyama, Eiji

N1 - Funding Information: The neutron diffraction experiments were conducted at the Materials and Life Science Experimental Facility of J-PARC under proposal No. 2018AM0016. Yutao Zhou is grateful to the China Scholarship Council for the financial support. Funding Information: The neutron diffraction experiments were conducted at the Materials and Life Science Experimental Facility of J-PARC under proposal No. 2018AM0016. Yutao Zhou is grateful to the China Scholarship Council for the financial support. Publisher Copyright: © 2022 Acta Materialia Inc.

PY - 2022/3

Y1 - 2022/3

N2 - The transformation and stabilization behaviors of the austenite (γ) phase during bainite transformation in the early stages of austempering treatment of low-alloy transformation-induced plasticity-aided bainitic ferrite (TBF) steel were investigated by in-situ neutron diffraction measurement and microstructure observation. Neutron diffraction peak profile analysis with a short time range resolution showed the changes in the phase fractions and the lattice constants of the α and γ phases in TBF steel during rapid cooling and austempering treatment. The γ phase with a low carbon concentration (γ(low-C)-Fe) immediately disappeared before the austempering time of 300 s. This indicates a remarkable increase in the lattice constant of the γ with a high carbon concentration (γ(high-C)-Fe) because of the bainite transformation of γ(low-C)-Fe and carbon partitioning to γ(high-C)-Fe. When the austempering time increased from 300 s to 3600 s, the volume fraction of γ(high-C)-Fe monotonically decreased and the lattice constant was hardly changed.

AB - The transformation and stabilization behaviors of the austenite (γ) phase during bainite transformation in the early stages of austempering treatment of low-alloy transformation-induced plasticity-aided bainitic ferrite (TBF) steel were investigated by in-situ neutron diffraction measurement and microstructure observation. Neutron diffraction peak profile analysis with a short time range resolution showed the changes in the phase fractions and the lattice constants of the α and γ phases in TBF steel during rapid cooling and austempering treatment. The γ phase with a low carbon concentration (γ(low-C)-Fe) immediately disappeared before the austempering time of 300 s. This indicates a remarkable increase in the lattice constant of the γ with a high carbon concentration (γ(high-C)-Fe) because of the bainite transformation of γ(low-C)-Fe and carbon partitioning to γ(high-C)-Fe. When the austempering time increased from 300 s to 3600 s, the volume fraction of γ(high-C)-Fe monotonically decreased and the lattice constant was hardly changed.

KW - Austempering treatment

KW - Carbon partitioning

KW - In-situ neutron diffraction

KW - Phase transformation

KW - Retained austenite

KW - TRIP-aided steel

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JO - Materialia

JF - Materialia

M1 - 101317

ER -

Austenite stabilization kinetics in early stages of austempering treatment in TRIP-aided steel using in-situ neutron diffraction technique

Abstract

Keywords

ASJC Scopus subject areas

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