Abstract
Microstructure formation and stress distribution during directional solidification are simulated using a phase field model for a binary alloy system. Nuclei are set as the initial condition, and the growth toward the liquid region is supposed. Cellular structure is formed as the crystal grows, and wavy pattern at the growing front is observed. Coalescence of the adjacent cells occurs under a certain condition, and then droplets and grooves of liquid phase are generated. The stress distributions in these complicated structures are then calculated, while only an elastic behavior is considered for simplicity. Relatively large tensile stress is generated in the interfacial region, and especially large stress concentration is observed when the droplets and grooves appear. When the stress dependency on the phase transformation is considered, the morphology is drastically varied. Also it reveals that the dependence of the chemical composition on the elastic constant affects the stress distribution.
