Experimental observation and phase-field modeling of interface morphological transition in unidirectional solidification

Depending on the relative strength of the interface energy anisotropy, a growing solidification I interface may develop into various distinguished patterns, such as dendritic, degenerate, and I seaweed patterns. This paper presents experimental observations of various irregular interface morphologies developed in a horizontal unidirectional solidification system using succinonitrile. Transitions from one interface pattern to another due to the variation of the temperature gradient and interface velocity are observed and documented. A 2-D phase-field model coupled with a heat conduction equation is solved to better understand the physics of the formation and transition of interface morphology. The model simulations illustrate similar effect of the temperature gradient on the interface morphology.