Mechanism of austenite formation from spheroidized microstructure in an intermediate Fe-0.1C-3.5Mn steel

Qingquan Lai, Mohamed Gouné, Astrid Perlade, Thomas Pardoen, Pascal Jacques, Olivier Bouaziz, Yves Bréchet

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28 Citations (Scopus)

Abstract

The austenitization from a spheroidized microstructure during intercritical annealing was studied in a Fe-0.1C-3.5Mn alloy. The austenite grains preferentially nucleate and grow from intergranular cementite. The nucleation at intragranular cementite is significantly retarded or even suppressed. The DICTRA software, assuming local equilibrium conditions, was used to simulate the austenite growth kinetics at various temperatures and for analyzing the austenite growth mechanism. The results indicate that both the mode and the kinetics of austenite growth strongly depend on cementite composition. With sufficiently high cementite Mn content, the austenite growth is essentially composed of two stages, involving the partitioning growth controlled by Mn diffusion inside ferrite, followed by a stage controlled by Mn diffusion within austenite for final equilibration. The partitioning growth results in a homogeneous distribution of carbon within austenite, which is supported by NanoSIMS carbon mapping.

Original languageEnglish
Pages (from-to)3375-3386
Number of pages12
JournalMetallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
Volume47
Issue number7
DOIs
Publication statusPublished - 4 May 2016
Externally publishedYes

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