Growth of bainitic ferrite and carbon partitioning during the early stages of bainite transformation in a 2 mass% silicon steel studied by in situ neutron diffraction, TEM and APT

I. B. Timokhina, K. D. Liss, D. Raabe, K. Rakha, H. Beladi, X. Y. Xiong, P. D. Hodgson

Research output: Contribution to journalArticleResearchpeer-review

Abstract

In situ neutron diffraction, transmission electron microscopy (TEM) and atom probe tomography (APT) have been used to study the early stages of bainite transformation in a 2 mass% Si nano-bainitic steel. It was observed that carbon redistribution between the bainitic ferrite and retained austenite at the early stages of the bainite transformation at low isothermal holding occurred in the following sequence: (i) formation of bainitic ferrite nuclei within carbon-depleted regions immediately after the beginning of isothermal treatment; (ii) carbon partitioning immediately after the formation of bainitic ferrite nuclei but substantial carbon diffusion only after 33 min of bainite isothermal holding; (iii) formation of the carbon-enriched remaining austenite in the vicinity of bainitic laths at the beginning of the transformation; (iv) segregation of carbon to the dislocations near the austenite/ferrite interface; and (v) homogeneous redistribution of carbon within the remaining austenite with the progress of the transformation and with the formation of bainitic ferrite colonies. Bainitic ferrite nucleated at internal defects or bainite/austenite interfaces as well as at the prior austenite grain boundary. Bainitic ferrite has been observed in the form of an individual layer, a colony of layers and a layer with sideplates at the early stages of transformation.

Original languageEnglish
Pages (from-to)399-414
Number of pages16
JournalJournal of Applied Crystallography
Volume49
DOIs
Publication statusPublished - 2016

Keywords

  • atom probe tomography
  • bainite transformation
  • bainitic ferrite
  • carbon content
  • neutron diffraction
  • retained austenite
  • transmission electron microscopy

Cite this

@article{a717a2ea57a444568c1d6c8143def61e,
title = "Growth of bainitic ferrite and carbon partitioning during the early stages of bainite transformation in a 2 mass{\%} silicon steel studied by in situ neutron diffraction, TEM and APT",
abstract = "In situ neutron diffraction, transmission electron microscopy (TEM) and atom probe tomography (APT) have been used to study the early stages of bainite transformation in a 2 mass{\%} Si nano-bainitic steel. It was observed that carbon redistribution between the bainitic ferrite and retained austenite at the early stages of the bainite transformation at low isothermal holding occurred in the following sequence: (i) formation of bainitic ferrite nuclei within carbon-depleted regions immediately after the beginning of isothermal treatment; (ii) carbon partitioning immediately after the formation of bainitic ferrite nuclei but substantial carbon diffusion only after 33 min of bainite isothermal holding; (iii) formation of the carbon-enriched remaining austenite in the vicinity of bainitic laths at the beginning of the transformation; (iv) segregation of carbon to the dislocations near the austenite/ferrite interface; and (v) homogeneous redistribution of carbon within the remaining austenite with the progress of the transformation and with the formation of bainitic ferrite colonies. Bainitic ferrite nucleated at internal defects or bainite/austenite interfaces as well as at the prior austenite grain boundary. Bainitic ferrite has been observed in the form of an individual layer, a colony of layers and a layer with sideplates at the early stages of transformation.",
keywords = "atom probe tomography, bainite transformation, bainitic ferrite, carbon content, neutron diffraction, retained austenite, transmission electron microscopy",
author = "Timokhina, {I. B.} and Liss, {K. D.} and D. Raabe and K. Rakha and H. Beladi and Xiong, {X. Y.} and Hodgson, {P. D.}",
year = "2016",
doi = "10.1107/S1600576716000418",
language = "English",
volume = "49",
pages = "399--414",
journal = "Journal of Applied Crystallography",
issn = "0021-8898",
publisher = "International Union of Crystallography",

}

Growth of bainitic ferrite and carbon partitioning during the early stages of bainite transformation in a 2 mass% silicon steel studied by in situ neutron diffraction, TEM and APT. / Timokhina, I. B.; Liss, K. D.; Raabe, D.; Rakha, K.; Beladi, H.; Xiong, X. Y.; Hodgson, P. D.

In: Journal of Applied Crystallography, Vol. 49, 2016, p. 399-414.

Research output: Contribution to journalArticleResearchpeer-review

TY - JOUR

T1 - Growth of bainitic ferrite and carbon partitioning during the early stages of bainite transformation in a 2 mass% silicon steel studied by in situ neutron diffraction, TEM and APT

AU - Timokhina, I. B.

AU - Liss, K. D.

AU - Raabe, D.

AU - Rakha, K.

AU - Beladi, H.

AU - Xiong, X. Y.

AU - Hodgson, P. D.

PY - 2016

Y1 - 2016

N2 - In situ neutron diffraction, transmission electron microscopy (TEM) and atom probe tomography (APT) have been used to study the early stages of bainite transformation in a 2 mass% Si nano-bainitic steel. It was observed that carbon redistribution between the bainitic ferrite and retained austenite at the early stages of the bainite transformation at low isothermal holding occurred in the following sequence: (i) formation of bainitic ferrite nuclei within carbon-depleted regions immediately after the beginning of isothermal treatment; (ii) carbon partitioning immediately after the formation of bainitic ferrite nuclei but substantial carbon diffusion only after 33 min of bainite isothermal holding; (iii) formation of the carbon-enriched remaining austenite in the vicinity of bainitic laths at the beginning of the transformation; (iv) segregation of carbon to the dislocations near the austenite/ferrite interface; and (v) homogeneous redistribution of carbon within the remaining austenite with the progress of the transformation and with the formation of bainitic ferrite colonies. Bainitic ferrite nucleated at internal defects or bainite/austenite interfaces as well as at the prior austenite grain boundary. Bainitic ferrite has been observed in the form of an individual layer, a colony of layers and a layer with sideplates at the early stages of transformation.

AB - In situ neutron diffraction, transmission electron microscopy (TEM) and atom probe tomography (APT) have been used to study the early stages of bainite transformation in a 2 mass% Si nano-bainitic steel. It was observed that carbon redistribution between the bainitic ferrite and retained austenite at the early stages of the bainite transformation at low isothermal holding occurred in the following sequence: (i) formation of bainitic ferrite nuclei within carbon-depleted regions immediately after the beginning of isothermal treatment; (ii) carbon partitioning immediately after the formation of bainitic ferrite nuclei but substantial carbon diffusion only after 33 min of bainite isothermal holding; (iii) formation of the carbon-enriched remaining austenite in the vicinity of bainitic laths at the beginning of the transformation; (iv) segregation of carbon to the dislocations near the austenite/ferrite interface; and (v) homogeneous redistribution of carbon within the remaining austenite with the progress of the transformation and with the formation of bainitic ferrite colonies. Bainitic ferrite nucleated at internal defects or bainite/austenite interfaces as well as at the prior austenite grain boundary. Bainitic ferrite has been observed in the form of an individual layer, a colony of layers and a layer with sideplates at the early stages of transformation.

KW - atom probe tomography

KW - bainite transformation

KW - bainitic ferrite

KW - carbon content

KW - neutron diffraction

KW - retained austenite

KW - transmission electron microscopy

UR - http://www.scopus.com/inward/record.url?scp=84964331046&partnerID=8YFLogxK

U2 - 10.1107/S1600576716000418

DO - 10.1107/S1600576716000418

M3 - Article

VL - 49

SP - 399

EP - 414

JO - Journal of Applied Crystallography

JF - Journal of Applied Crystallography

SN - 0021-8898

ER -