Interaction of precipitation with austenite-to-ferrite phase transformation in vanadium micro-alloyed steels

Journal article (2019)

Authors

C. Ioannidou (OLD) MSE-1
S.E. Offerman (OLD) MSE-1
A. Navarro Lopez (OLD) MSE-1
Arjan Rijkenberg Tata Steel, 1970 CA IJmuiden, the Netherlands
Robert M. Dalgliesh Rutherford Appleton Laboratory
S. Kölling Eindhoven University of Technology
Vitaliy Bliznuk Universiteit Gent
C. Pappas RST/Neutron and Positron Methods in Materials - AS
J. Sietsma Materials Science and Engineering
A.A. van Well RID/Algemeen/Bedrijfsondersteuning
Research Group
(OLD) MSE-1
Copyright: © 2019 C. Ioannidou, Z. Arechabaleta Guenechea, A. Navarro Lopez, Arjan Rijkenberg, Robert M. Dalgliesh, S. Kölling, Vitaliy Bliznuk, C. Pappas, J. Sietsma, A.A. van Well, S.E. Offerman
DOI: https://doi.org/10.1016/j.actamat.2019.09.046
More Info
expand_more

Published Date

2019

Language

English

Reuse Rights

Other than for strictly personal use, it is not permitted to download, forward or distribute the text or part of it, without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license such as Creative Commons.

Research Group

(OLD) MSE-1

Abstract

The precipitation kinetics of vanadium carbides and its interaction with the austenite-to-ferrite phase transformation is studied in two micro-alloyed steels that differ in vanadium and carbon concentrations by a factor of two, but have the same vanadium-to-carbon atomic ratio of 1:1. Dilatometry is used for heat-treating the specimens and studying the phase transformation kinetics during annealing at isothermal holding temperatures of 900, 750 and 650 °C for up to 10 h. Small-Angle Neutron Scattering (SANS) and Atom Probe Tomography (APT) measurements are performed to study the vanadium carbide precipitation kinetics. Vanadium carbide precipitation is not observed after annealing for 10 h at 900 and 750 °C, which is contrary to predictions from thermodynamic equilibrium calculations. Vanadium carbide precipitation is only observed during or after the austenite-to-ferrite phase transformation at 650 °C. The precipitate volume fraction and mean radius continuously increase as holding time increases, while the precipitate number density starts to decrease after 20 min, which corresponds to the time at which the austenite-to-ferrite phase transformation is finished. This indicates that nucleation and growth are dominant during the first 20 min, while later precipitate growth with soft impingement (overlapping diffusion fields) and coarsening take place. APT shows gradual changes in the precipitate chemical composition during annealing at 650 °C, which finally reaches a 1:1 atomic ratio of vanadium-to-carbon in the core of the precipitates after 10 h.

Files

Chrysoula_Ioannidou_ActaMater_... (pdf)
(pdf | 5.31 Mb)
- Embargo expired in 26-03-2020
Unknown license