5th International Conference on Advances in Solidification Processes (ICASP-5) 5th International Symposium on Cutting Edge of Computer Simulation of Solidification, Casting and Refining (CSSCR-5)

We have performed the large-scale molecular dynamics simulations for nucleation, solidification and microstructure formation [1] and found various new insights such as the heterogeneity in homogeneous nucleation [2] and decrease of the averaged grain boundary mobility during the grain growth [3]. Although these studies were performed using pure metallic system for simplicity, the most of practical structural materials consists of alloys. Therefore, nucleation and solidification processes for various alloy systems are investigated by molecular dynamics simulation in this study. Regarding the homogeneous nucleation from undercooled melt of Ni-Al alloy, the B2 structure is directly nucleated from the undercooled melt of Ni-50mol%Al, whereas no specific compound is not nucleated but mixture of bcc and fcc phases appeared from Ni-25mol%Al. The heterogeneous nucleation in Al melt inoculated with Ti and Ti3Al particles as grain refiners are performed and the relationship between the particle size and the undercooled temperature needed for the heterogeneous nucleation are discussed. The preferential facet of the hcp Ti surface for the heterogeneous nucleation of Al melt is also investigated. Moreover, interfacial properties such as the solid-liquid interfacial energy and the kinetic coefficient are closely examined for Fe-Cr system by focusing on the concentration dependence. Our cutting-edge results will be introduced in the presentation. [1] Y. Shibuta, et al. JOM 67 (2015) 1793. [2] Y. Shibuta, et al, Nature Comm. 8 (2017) 10. [3] S. Okita, et al., Acta Mater. 153 (2018) 108