EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

In alloy casting, the formation process of equiaxed structure is still poorly understood. The most difficult point in the formation process of equiaxed structure is that the equiaxed grains can move in liquid phase due to forced convection and buoyancy force. To understand the behavior of 3D equiaxed grains, the time-resolved X-ray tomography was performed as a state-of-the-art experimental method [T. Narumi et al., J. Jpn. Inst. Met., 70 (2020) 339-346]. In the observation, the floating-up and subsequent stacking on the top region of multiple equiaxed dendritic grains were observed successfully. On the other hand, to see the phenomenon in more detail, much higher spatiotemporal resolution is desirable. In the simulation study, we enabled the expression of formation process of equiaxed structure using the phase-field and lattice Boltzmann models [S. Sakane et al., Comp. Mater. Sci., 178 (2020) 109639, T. Takaki et al., Comp. Mater. Sci., 147 (2018) 124–131]. Although, in the study, we succeeded to express the motion of a massive number of equiaxed grains, the lack of material properties is the biggest issue in the simulation. Thus, an integration of experiment and simulation is indispensable in order to overcome those problem. In this study, we develop a data-assimilation system integrating experiment and simulation in the phenomenon where an isolated equiaxed dendrite is settling in liquid. To confirm the validity of the developed system, the twin experiments are conducted for the phenomenon.