Imperial College London
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ProfessorBaptisteGault

Faculty of Engineering, Department of Materials

Professor of Atomic-Scale Characterization
 
 
 
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b.gault

 
 
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Location

 

Royal School of MinesSouth Kensington Campus

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Summary

 

Publications

Citation

BibTex format

@article{Benzing:2019:10.1016/j.actamat.2019.01.003,
author = {Benzing, JT and Kwiatkowski, da Silva A and Morsdorf, L and Bentley, J and Ponge, D and Dutta, A and Han, J and McBride, JR and Van, Leer B and Gault, B and Raabe, D and Wittig, JE},
doi = {10.1016/j.actamat.2019.01.003},
journal = {Acta Materialia},
pages = {512--530},
title = {Multi-scale characterization of austenite reversion and martensite recovery in a cold-rolled medium-Mn steel},
url = {http://dx.doi.org/10.1016/j.actamat.2019.01.003},
volume = {166},
year = {2019}
}
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RIS format (EndNote, RefMan)

TY  - JOUR
AB  - © 2019 Acta Materialia Inc.  A medium-Mn steel (Fe-12Mn-3Al-0.05C wt%) was designed using Thermo-Calc ® simulations to balance the fraction and stacking fault energy of reverted austenite. Intercritical annealing for 0.5, 8 and 48 h was carried out at 585 °C to investigate the microstructural evolution. X-ray diffraction (XRD), electron backscatter diffraction (EBSD), 3-dimensional EBSD, energy-dispersive spectroscopy via scanning-transmission electron microscopy (STEM-EDS) and atom probe tomography (APT) enable characterization of phase fraction, grain area, grain morphology and alloy partitioning. An increase in annealing time from 0.5 h to 48 h increases the amount of ultrafine-grained (UFG) reverted austenite from 3 to 40 vol %. EBSD and TEM reveal multiple morphologies of UFG austenite (equiaxed, rod-like and plate-like). In addition, most of the remaining microstructure consists of recovered α′-martensite that resembles the cold-rolled state, as well as a relatively small fraction of UFG ferrite (i.e., only a small amount of martensite recrystallization occurs). Multi-scale characterization results show that the location within the cold-rolled microstructure has a strong influence on boundary mobility and grain morphology during austenite reversion. Results from APT reveal Mn-decoration of dislocation networks and low-angle lath boundaries in the recovered α′-martensite, but an absence of Mn-decoration of defects in the vicinity of austenite grains, thereby promoting recovery. STEM-EDS and APT reveal Mn depletion zones in the ferrite/recovered α′-martensite near austenite boundaries, whereas gradients of C and Mn co-partitioning are visible within some of the austenite grains after annealing for 0.5 h. Relatively flat C-enriched austenite boundaries are present even after 8 h of annealing and indicate certain boundaries possess low mobility. At later stages the growth of austenite followed the local equilibrium
AU  - Benzing,JT
AU  - Kwiatkowski,da Silva A
AU  - Morsdorf,L
AU  - Bentley,J
AU  - Ponge,D
AU  - Dutta,A
AU  - Han,J
AU  - McBride,JR
AU  - Van,Leer B
AU  - Gault,B
AU  - Raabe,D
AU  - Wittig,JE
DO  - 10.1016/j.actamat.2019.01.003
EP  - 530
PY  - 2019///
SN  - 1359-6454
SP  - 512
TI  - Multi-scale characterization of austenite reversion and martensite recovery in a cold-rolled medium-Mn steel
T2  - Acta Materialia
UR  - http://dx.doi.org/10.1016/j.actamat.2019.01.003
VL  - 166
ER  -
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