TY - JOUR
T1 - Time-resolved and insitu observation of δ-γ transformation during unidirectional solidification in Fe-C alloys
AU - Nishimura, Tomohiro
AU - Morishita, Kohei
AU - Yoshiya, Masato
AU - Nagira, Tomoya
AU - Yasuda, Hideyuki
N1 - Funding Information:
The in-situ observations and measurements using synchrotron radiation X-rays were performed as general projects at BL20B2 and BL20XU of SPring-8 (JASRI), Japan. The authors acknowledge valuable discussions in a research group "Visualization of Solidification" of the 19th Committee on Steelmaking of JSPS. The authors also acknowledge financial support from Heterogeneous Structure Control: Towards Innovative Development of Metallic Structural Materials of the Industry-Academia Collaborative R&D Program (JST). The X-ray imaging technique that was developed with a funding from a Grant-in-Aid for Scientific Research (S) (No. 17H06155) allowed the authors to observe solidification phenomena and to measure diffraction spots. We thank Andrew Jackson, PhD, from Edanz Group (www.edanzediting.com/ac) for editing a draft of this manuscript.
Funding Information:
The in-situ observations and measurements using synchrotron radiation X-rays were performed as general projects at BL20B2 and BL20XU of SPring-8 (JASRI), Japan. The authors acknowledge valuable discussions in a research group “Visualization of Solidification” of the 19th Committee on Steelmaking of JSPS. The authors also acknowledge financial support from Heterogeneous Structure Control: Towards Innovative Development of Metallic Structural Materials of the Industry–Academia Collaborative R&D Program (JST). The X-ray imaging technique that was developed with a funding from a Grant-in-Aid for Scientific Research (S) (No. 17H06155) allowed the authors to observe solidification phenomena and to measure diffraction spots. We thank Andrew Jackson, PhD, from Edanz Group (www.edanzediting.com/ac) for editing a draft of this manuscript.
PY - 2020
Y1 - 2020
N2 - Time-resolved and in-situ observations using synchrotron radiation X-rays successfully proved that a massive-like transformation, in which the γ phase was produced through the solid-solid transformation and partitioning of substitute elements such as Mn and Si at the δ-γ interface was negligible, was selected in the unidirectional solidification of 0.3 mass% C steel at a pulling rate of 50 μm/s. The massive-like transformation produced fine γ grains near the front of the δ-γ interface. The coarse γ grains also grew behind the fine γ grains along the temperature gradient. Distance between the δ-γ front and the advancing front of coarse γ grains was as short as 200 μm. Namely, the fine γ grains disappeared within 10 s owing to growth of coarse γ grains. In addition, the observation of the δ-γ interface confirmed that a transition from the diffusion-controlled γ growth to the massive-like γ growth occurred at a growth velocity of 5 μm/s. Thus, the massive-like transformation is dominantly selected in the carbon steel during conventional solidification processes.
AB - Time-resolved and in-situ observations using synchrotron radiation X-rays successfully proved that a massive-like transformation, in which the γ phase was produced through the solid-solid transformation and partitioning of substitute elements such as Mn and Si at the δ-γ interface was negligible, was selected in the unidirectional solidification of 0.3 mass% C steel at a pulling rate of 50 μm/s. The massive-like transformation produced fine γ grains near the front of the δ-γ interface. The coarse γ grains also grew behind the fine γ grains along the temperature gradient. Distance between the δ-γ front and the advancing front of coarse γ grains was as short as 200 μm. Namely, the fine γ grains disappeared within 10 s owing to growth of coarse γ grains. In addition, the observation of the δ-γ interface confirmed that a transition from the diffusion-controlled γ growth to the massive-like γ growth occurred at a growth velocity of 5 μm/s. Thus, the massive-like transformation is dominantly selected in the carbon steel during conventional solidification processes.
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U2 - 10.2355/isijinternational.ISIJINT-2019-636
DO - 10.2355/isijinternational.ISIJINT-2019-636
M3 - Article
AN - SCOPUS:85086223475
VL - 60
SP - 930
EP - 938
JO - Transactions of the Iron and Steel Institute of Japan
JF - Transactions of the Iron and Steel Institute of Japan
SN - 0915-1559
IS - 5
ER -