Impact of Precipitate Morphology on the Dissolution and Grain-Coarsening Behavior of a Ti-Nb Microalloyed Linepipe Steel
The relationship between precipitate morphology and dissolution on grain coarsening behavior was studied in two Ti-Nb microalloyed Linepipe (LP) Steels. The developed understanding highlights the importance of the complex relationship between precipitate constitutive make-up, dissolution mechanism a...
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doaj-e054ef1950dc4268b7f2a2ef5ead4e712020-11-25T01:38:38ZengMDPI AGMetals2075-47012020-01-011018910.3390/met10010089met10010089Impact of Precipitate Morphology on the Dissolution and Grain-Coarsening Behavior of a Ti-Nb Microalloyed Linepipe SteelGregorio Solis-Bravo0Matthew Merwin1C. Isaac Garcia2Ferrous Physical Metallurgy Group, University of Pittsburgh, Pittsburgh, PA 15261, USAUnited States Steel Corporation, Pittsburgh, PA 15120, USAFerrous Physical Metallurgy Group, University of Pittsburgh, Pittsburgh, PA 15261, USAThe relationship between precipitate morphology and dissolution on grain coarsening behavior was studied in two Ti-Nb microalloyed Linepipe (LP) Steels. The developed understanding highlights the importance of the complex relationship between precipitate constitutive make-up, dissolution mechanism and grain boundary (GB) pinning force. Equilibrium-based empirical solubility products were used to calculate precipitate volume fractions and compared to experimental measurements. Scanning Electron Microscopy (SEM), Electron Backscatter Diffraction (EBSD) and Electron Probe Micro-Analysis (EPMA) were conducted on bulk samples. Transmission Electron Microscopy (TEM)-based techniques were used on C-replica extractions and thin-foils. A retardation in the grain-coarsening temperature compared to the predicted coarsening temperature based on equilibrium calculations was noticed. In addition, a consistent NbC epitaxial formation over pre-existing TiN was observed. The resulting reduction in total precipitate/matrix interface area and the low energy of the TiN/NbC interface are pointed to as responsible mechanisms for the retardation in the kinetics of precipitates’ dissolution. This dissolution retardation mechanism suggests that a lower Nb content might be effective in controlling the grain coarsening behavior of austenite.https://www.mdpi.com/2075-4701/10/1/89grain coarseningprecipitate dissolutionepitaxial precipitationti-nb microalloyed steellinepipe |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Gregorio Solis-Bravo Matthew Merwin C. Isaac Garcia |
spellingShingle |
Gregorio Solis-Bravo Matthew Merwin C. Isaac Garcia Impact of Precipitate Morphology on the Dissolution and Grain-Coarsening Behavior of a Ti-Nb Microalloyed Linepipe Steel Metals grain coarsening precipitate dissolution epitaxial precipitation ti-nb microalloyed steel linepipe |
author_facet |
Gregorio Solis-Bravo Matthew Merwin C. Isaac Garcia |
author_sort |
Gregorio Solis-Bravo |
title |
Impact of Precipitate Morphology on the Dissolution and Grain-Coarsening Behavior of a Ti-Nb Microalloyed Linepipe Steel |
title_short |
Impact of Precipitate Morphology on the Dissolution and Grain-Coarsening Behavior of a Ti-Nb Microalloyed Linepipe Steel |
title_full |
Impact of Precipitate Morphology on the Dissolution and Grain-Coarsening Behavior of a Ti-Nb Microalloyed Linepipe Steel |
title_fullStr |
Impact of Precipitate Morphology on the Dissolution and Grain-Coarsening Behavior of a Ti-Nb Microalloyed Linepipe Steel |
title_full_unstemmed |
Impact of Precipitate Morphology on the Dissolution and Grain-Coarsening Behavior of a Ti-Nb Microalloyed Linepipe Steel |
title_sort |
impact of precipitate morphology on the dissolution and grain-coarsening behavior of a ti-nb microalloyed linepipe steel |
publisher |
MDPI AG |
series |
Metals |
issn |
2075-4701 |
publishDate |
2020-01-01 |
description |
The relationship between precipitate morphology and dissolution on grain coarsening behavior was studied in two Ti-Nb microalloyed Linepipe (LP) Steels. The developed understanding highlights the importance of the complex relationship between precipitate constitutive make-up, dissolution mechanism and grain boundary (GB) pinning force. Equilibrium-based empirical solubility products were used to calculate precipitate volume fractions and compared to experimental measurements. Scanning Electron Microscopy (SEM), Electron Backscatter Diffraction (EBSD) and Electron Probe Micro-Analysis (EPMA) were conducted on bulk samples. Transmission Electron Microscopy (TEM)-based techniques were used on C-replica extractions and thin-foils. A retardation in the grain-coarsening temperature compared to the predicted coarsening temperature based on equilibrium calculations was noticed. In addition, a consistent NbC epitaxial formation over pre-existing TiN was observed. The resulting reduction in total precipitate/matrix interface area and the low energy of the TiN/NbC interface are pointed to as responsible mechanisms for the retardation in the kinetics of precipitates’ dissolution. This dissolution retardation mechanism suggests that a lower Nb content might be effective in controlling the grain coarsening behavior of austenite. |
topic |
grain coarsening precipitate dissolution epitaxial precipitation ti-nb microalloyed steel linepipe |
url |
https://www.mdpi.com/2075-4701/10/1/89 |
work_keys_str_mv |
AT gregoriosolisbravo impactofprecipitatemorphologyonthedissolutionandgraincoarseningbehaviorofatinbmicroalloyedlinepipesteel AT matthewmerwin impactofprecipitatemorphologyonthedissolutionandgraincoarseningbehaviorofatinbmicroalloyedlinepipesteel AT cisaacgarcia impactofprecipitatemorphologyonthedissolutionandgraincoarseningbehaviorofatinbmicroalloyedlinepipesteel |
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