Simulation of dendritic-eutectic growth with the phase-field method

Solidification is an important process in many alloy processing routes. The solidified microstructure of alloys is usually made up of dendrites, eutectics or a combination of both. The evolving morphologies are largely determined by the solidification process and thus many materials properties are dependent on the processing conditions. While the growth of either type of microstructure is well-investigated, there is little information on the coupled growth of both microstructures. This work aims to close this gap by formulating a phase -field model capable of reproducing dendritic, eutectic as well as dendritic-eutectic growth. Following this, two-dimensional simulations are conducted which show all three types of microstructures depending on the composition and processing conditions. The effect of the dendritic-eutectic growth on the microstructural lengths, which determine materials properties, is investigated and the morphological hysteresis between eutectic growth and dendritic-eutectic growth is studied by employing solidification velocity jumps. Finally, qualitative three-dimensional simulations are conducted to test for morphological changes in the eutectic.

Automated summary

Solidification is a crucial process in alloy processing, and the resulting microstructure of alloys is typically composed of dendrites, eutectics, or both. The growth of these microstructures greatly affects materials properties, but little is known about the coupled growth of both microstructures. This study addresses this gap by developing a phase-field model that can simulate dendritic, eutectic, and dendritic-eutectic growth. Two-dimensional simulations demonstrate the presence of all three microstructures depending on composition and processing conditions. The impact of dendritic-eutectic growth on microstructural lengths, which determine materials properties, is investigated and hysteresis between eutectic growth and dendritic-eutectic growth is studied using solidification velocity jumps. Finally, qualitative three-dimensional simulations are conducted to examine morphological changes in the eutectic.