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Real Time Observation of Martensite Transformation for a 0.4C Low Alloyed Steel by Neutron Diffraction

32 Pages Posted: 25 Sep 2019 Publication Status: Accepted

See all articles by Yanxu Wang

Yanxu Wang

National Institute for Materials Science - Innovative Structural Materials Association (ISMA)

Yo Tomota

National Institute for Materials Science - Innovative Structural Materials Association (ISMA); National Institute of Advanced Industrial Science and Technology (AIST)

Takahito Ohmura

National Institute for Materials Science - Innovative Structural Materials Association (ISMA)

Satoshi Morooka

Japan Atomic Energy Agency - Materials Sciences Research Center

Wu Gong

National Institute for Materials Science - Elements Strategy Initiative for Structural Materials (ESISM)

Stefanus Harjo

Japan Atomic Energy Agency - J-PARC Center; National Institute for Materials Science - Elements Strategy Initiative for Structural Materials (ESISM)

Abstract

A high-intensity and high-resolution neutron diffractometer with a thermomechanically controlled processing simulator was employed in-situ to investigate martensite transformation behavior with and without ausforming for a medium carbon low-alloy steel. Serial neutron diffraction profiles have revealed that the transformation behavior could be successfully monitored during fast cooling and during the ausforming process. The hkl diffraction intensity of austenite increased at the beginning of transformation due to the primary extinction effect. The fresh martensite exhibits a body-centered tetragonal structure when it forms immediately below the martensite start (Ms) temperature, and its c/a ratio decreases rapidly as time elapses. The lattice parameter and the full width at half maximum of austenite peaks significantly decreases and increases upon martensite transformation, respectively. Ausforming slightly increases the Ms temperature, the amount of retained austenite at RT and the austenite lattice parameter. The dislocation densities in martensite and the retained austenite estimated using the convolutional multiple whole profile fitting method increase by ausforming.

Keywords: Martensite transformation, In-situ neutron diffraction, Ausforming, Low-alloy steel, Lattice parameter

Suggested Citation

Wang, Yanxu and Tomota, Yo and Ohmura, Takahito and Morooka, Satoshi and Gong, Wu and Harjo, Stefanus, Real Time Observation of Martensite Transformation for a 0.4C Low Alloyed Steel by Neutron Diffraction. Available at SSRN: https://ssrn.com/abstract=3458134 or http://dx.doi.org/10.2139/ssrn.3458134

Yanxu Wang (Contact Author)

National Institute for Materials Science - Innovative Structural Materials Association (ISMA) ( email )

Japan

Yo Tomota

National Institute for Materials Science - Innovative Structural Materials Association (ISMA)

Japan

National Institute of Advanced Industrial Science and Technology (AIST)

1-3-1 Kasumigaseki
Chiyoda-ku
Tokyo, 100-8921
Japan

Takahito Ohmura

National Institute for Materials Science - Innovative Structural Materials Association (ISMA)

Japan

Satoshi Morooka

Japan Atomic Energy Agency - Materials Sciences Research Center ( email )

Tokai, Ibaraki
Japan

Wu Gong

National Institute for Materials Science - Elements Strategy Initiative for Structural Materials (ESISM)

Japan

Stefanus Harjo

Japan Atomic Energy Agency - J-PARC Center ( email )

Japan

National Institute for Materials Science - Elements Strategy Initiative for Structural Materials (ESISM) ( email )

Japan

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