Effects of Q&P processing conditions on austenite carbon enrichment studied by in situ high-energy x-ray diffraction experiments
Language
en
Article de revue
This item was published in
Metals. 2017, vol. 7, n° 7, p. 232
MDPI
English Abstract
We report the first ultra-fast time-resolved quantitative information on the quenching and partitioning process of conventional high-strength steel by an in situ high-energy X-ray diffraction (HEXRD) experiment. The time ...Read more >
We report the first ultra-fast time-resolved quantitative information on the quenching and partitioning process of conventional high-strength steel by an in situ high-energy X-ray diffraction (HEXRD) experiment. The time and temperature evolutions of phase fractions, their carbon content, and internal stresses were determined and discussed for different process parameters. It is shown that the austenite-to-martensite transformation below the martensite start temperature Ms is followed by a stage of fast carbon enrichment in austenite during isothermal holding at both 400 and 450 °C. The analysis proposed supports the concurrent bainite transformation and carbon diffusion from martensite to austenite as the main mechanisms of this enrichment. Furthermore, we give evidence that high hydrostatic tensile stresses in austenite are produced during the final quenching, and must be taken into account for the estimation of the carbon content in austenite. Finally, a large amount of carbon is shown to be trapped in the microstructure.Read less <
English Keywords
steel
martensite
bainite
Q&P
synchrotron
HEXRD
TRIP
ANR Project
Partition du carbone dans les phases ferritiques nanostructurées: cinétiques et microstructures - ANR-14-CE07-0029
Design des Alliages Métalliques pour Allègement des Structures - ANR-11-LABX-0008
Design des Alliages Métalliques pour Allègement des Structures - ANR-11-LABX-0008
Origin
Hal imported