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Microstructure evolution during high-temperature partitioning of a medium-Mn quenching and partitioning steel. / Ayenampudi, S.; Celada-Casero, C.; Sietsma, J.; Santofimia, M. J.

In: Materialia, Vol. 8, 100492, 2019.

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@article{7e9500ed588546a1b0d97bda3c3c2803,
title = "Microstructure evolution during high-temperature partitioning of a medium-Mn quenching and partitioning steel",
abstract = "Medium-Mn Quenching & Partitioning (Q&P) steels have been recently considered as potential candidates for the 3rd generation advanced high-strength steels. The processing of these steels aims to induce the partitioning of substitutional alloying elements from martensite to austenite during an isothermal treatment at high temperature, where the diffusivity of substitutional alloying elements is sufficiently high. In this way, austenite increases its concentration of austenite-stabilising elements and thus its thermal stability. The present study aims to investigate the microstructural evolution during high temperature partitioning treatments in a medium-Mn steel and the possible occurrence of additional phase transformations that may compete with the process of atomic partitioning between martensite and austenite. Q&P routes in which the partitioning steps take place in the range of 400 °C–600 °C for times up to 3600 s were investigated. The final microstructures display an increased fraction of retained austenite with increasing holding times during partitioning at 400 °C, while at higher partitioning temperatures, 450 °C–600 °C, leads to cementite precipitation in austenite films and pearlite formation in blocky austenite, resulting in a decrease of the fraction of retained austenite with the holding time. This observation is supported with theoretical calculations of the volume change, suggesting that for maximising the fraction of retained austenite, short holding times are preferred during partitioning at high temperatures. Observations from the current study reveal that the successful application of high-temperature partitioning treatments in medium-Mn steels requires microstructure design strategies to minimize or suppress competitive reactions.",
keywords = "Austenite stability, Carbon partitioning, High-temperature partitioning, Medium manganese steel, Quenching and partitioning",
author = "S. Ayenampudi and C. Celada-Casero and J. Sietsma and Santofimia, {M. J.}",
year = "2019",
doi = "10.1016/j.mtla.2019.100492",
language = "English",
volume = "8",
journal = "Acta Materialia",
issn = "1359-6454",
publisher = "Elsevier",

}

RIS

TY - JOUR

T1 - Microstructure evolution during high-temperature partitioning of a medium-Mn quenching and partitioning steel

AU - Ayenampudi, S.

AU - Celada-Casero, C.

AU - Sietsma, J.

AU - Santofimia, M. J.

PY - 2019

Y1 - 2019

N2 - Medium-Mn Quenching & Partitioning (Q&P) steels have been recently considered as potential candidates for the 3rd generation advanced high-strength steels. The processing of these steels aims to induce the partitioning of substitutional alloying elements from martensite to austenite during an isothermal treatment at high temperature, where the diffusivity of substitutional alloying elements is sufficiently high. In this way, austenite increases its concentration of austenite-stabilising elements and thus its thermal stability. The present study aims to investigate the microstructural evolution during high temperature partitioning treatments in a medium-Mn steel and the possible occurrence of additional phase transformations that may compete with the process of atomic partitioning between martensite and austenite. Q&P routes in which the partitioning steps take place in the range of 400 °C–600 °C for times up to 3600 s were investigated. The final microstructures display an increased fraction of retained austenite with increasing holding times during partitioning at 400 °C, while at higher partitioning temperatures, 450 °C–600 °C, leads to cementite precipitation in austenite films and pearlite formation in blocky austenite, resulting in a decrease of the fraction of retained austenite with the holding time. This observation is supported with theoretical calculations of the volume change, suggesting that for maximising the fraction of retained austenite, short holding times are preferred during partitioning at high temperatures. Observations from the current study reveal that the successful application of high-temperature partitioning treatments in medium-Mn steels requires microstructure design strategies to minimize or suppress competitive reactions.

AB - Medium-Mn Quenching & Partitioning (Q&P) steels have been recently considered as potential candidates for the 3rd generation advanced high-strength steels. The processing of these steels aims to induce the partitioning of substitutional alloying elements from martensite to austenite during an isothermal treatment at high temperature, where the diffusivity of substitutional alloying elements is sufficiently high. In this way, austenite increases its concentration of austenite-stabilising elements and thus its thermal stability. The present study aims to investigate the microstructural evolution during high temperature partitioning treatments in a medium-Mn steel and the possible occurrence of additional phase transformations that may compete with the process of atomic partitioning between martensite and austenite. Q&P routes in which the partitioning steps take place in the range of 400 °C–600 °C for times up to 3600 s were investigated. The final microstructures display an increased fraction of retained austenite with increasing holding times during partitioning at 400 °C, while at higher partitioning temperatures, 450 °C–600 °C, leads to cementite precipitation in austenite films and pearlite formation in blocky austenite, resulting in a decrease of the fraction of retained austenite with the holding time. This observation is supported with theoretical calculations of the volume change, suggesting that for maximising the fraction of retained austenite, short holding times are preferred during partitioning at high temperatures. Observations from the current study reveal that the successful application of high-temperature partitioning treatments in medium-Mn steels requires microstructure design strategies to minimize or suppress competitive reactions.

KW - Austenite stability

KW - Carbon partitioning

KW - High-temperature partitioning

KW - Medium manganese steel

KW - Quenching and partitioning

UR - http://www.scopus.com/inward/record.url?scp=85073197481&partnerID=8YFLogxK

U2 - 10.1016/j.mtla.2019.100492

DO - 10.1016/j.mtla.2019.100492

M3 - Article

VL - 8

JO - Acta Materialia

T2 - Acta Materialia

JF - Acta Materialia

SN - 1359-6454

M1 - 100492

ER -

ID: 62169832