@article{2cd01f26a71941ffb7781c73fa682f77,
title = "Dendrite fragmentation induced by massive-like δ–γ transformation in Fe–C alloys",
abstract = "Dendrite arm fragmentation is considered in solidification structure tailoring. Time-resolved and in situ imaging using synchrotron radiation X-rays allows the observation of dendrite arm fragmentation in Fe–C alloys. Here we report a dendrite arm fragmentation mechanism. A massive-like transformation from ferrite to austenite rather than the peritectic reaction occurs during or after ferrite solidification. The transformation produces refined austenite grains and ferrite–austenite boundaries in dendrite arms. The austenite grains are fragmented by the liquid phase that is produced at the grain boundary. In unidirectional solidification, a slight increase in temperature moves the ferrite–austenite interface backwards and promotes detachment of the primary and secondary arms at the δ–γ interface via a reverse peritectic reaction. The results show a massive-like transformation inducing the dendrite arm fragmentation has a role in formation of the solidification structure and the austenite grain structures in the Fe–C alloys.",
author = "Hideyuki Yasuda and Kohei Morishita and Noriaki Nakatsuka and Tomohiro Nishimura and Masato Yoshiya and Akira Sugiyama and Kentaro Uesugi and Akihisa Takeuchi",
note = "Funding Information: Observations at the synchrotron radiation facility SPring-8 were performed as general projects (2011B1247, 2012A1269, 2016A1454, 2017A1336, and 2018B1521) at BL20B2 and BL20XU of SPring-8 (JASRI), Japan. H. Yasuda, K. Morishita, and M. Yoshiya acknowledge financial support from the research group Visualization of Solidification of the 19th Committee on Steelmaking of the Japan Society for the Promotion of Science, and from Heterogeneous Structure Control: Towards Innovative Development of Metallic Structural Materials of the Industry–Academia Collaborative R & D Program (JST). The X ray transmission imaging that was developed with funding from a Grant-in-Aid for Scientific Research (S) (No. 17H06155) allowed the authors to observe solidification phenomena in Fe-based alloys. We thank Dr. T. Nagira, from Joining and Welding Research Institute, Osaka University, for his support during the initial stages of this study. We also thank Helen McPherson, PhD, and Laura Kuhar, PhD, from Edanz Group (www.edanzediting.com/ac) for editing a draft of this manuscript. Publisher Copyright: {\textcopyright} 2019, The Author(s). Copyright: Copyright 2019 Elsevier B.V., All rights reserved.",
year = "2019",
month = dec,
day = "1",
doi = "10.1038/s41467-019-11079-y",
language = "English",
volume = "10",
journal = "Nature Communications",
issn = "2041-1723",
publisher = "Nature Publishing Group",
number = "1",
}