Characterization of dendritic growth in Fe–C system using time-resolved X-ray tomography and physics-based filtering. (May 2019)

• Record Type: Journal Article
• Authors: Yasuda, H; Kawarasaki, T; Tomiyori, Y; Kato, Y; Morishita, K
• Is Part Of: IOP conference series. Volume 529(2019)
• Publication Date: 2019-05
• Subjects: Materials science -- Periodicals; 620.1105
• DOI: 10.1088/1757-899X/529/1/012023
• Languages: English
• ISSNs: 1757-8981

Abstract

Abstract: Time-resolved in situ tomography of dendritic growth in Fe–0.45 mass% C carbon steel was performed using synchrotron radiation X-rays at SPring-8 synchrotron radiation facility (Japan) with improvement of the image quality using a physics-based filter. The voxel size of the reconstructed image was approximately 6.5 μm × 6.5 μm × 6.5 μm, and the time resolution (duration of 360° rotation) was 4 s (0.25 rps). Three-dimensional images of the dendrites were reconstructed even without image processing; however, the low contrast resolution in Fe–C alloys led to poor image quality. Consequently, it was impossible to precisely track the solid/liquid interface or evaluate the average curvature. To improve the image quality, a physics-based filter (a PF filter) was developed using a phase-field model. In the PF filter, images were retrieved in terms of interface curvature. The PF filter significantly improved the computed tomography image quality. As a result, dendritic growth was clearly observed even in Fe–C alloys. Moreover, the average curvature of the solid/liquid interface was evaluated as a function of solidification time (solid fraction). The ability to systematically characterize growing dendrites will be beneficial for modeling and simulation of solidification phenomena.