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)

Microsegregation has a great influence on properties of materials such as mechanical and corrosive properties and it entirely depends on size and morphology of solidification microstructure. Although a number of efforts have been devoted to understanding and controlling of microsegregation in alloy systems, little has been clarified about microsegregation behavior at grain boundaries formed by growth of differently-oriented dendrites. Quantitative phase-field simulations have become one of the most powerful approaches for studying solidification phenomena and they have recently been employed in studies on competitive growth of dendrites in bi-crystal systems. Importantly, it is possible to analyze detail of microsegregation behavior using a quantitative phase-field model for two-sided asymmetric diffusion. In this study, therefore, we investigate microsegregation behavior at grain boundaries by means of two-dimensional quantitative phase-field simulations of directional solidification in bi-crystal systems. Our focus is placed on grain boundaries which are formed by two columnar dendrites; one is favorably-oriented (FO) dendrite and the other is unfavorably-orientated (UO) dendrites against the direction of temperature gradient. The microsegregation at the grain boundaries are investigated by changing the inclination angles of UO dendrite against the temperature gradient. The simulations are accelerated by using parallel computing on graphics processing unit (GPU) and by using moving frame scheme.