Effect of laser shock on lamellar eutectic growth: A phase-field study

Abstract Eutectic growth trajectory is a temperature-dependent important behavior that concerns interface stability and subsequent solidification microstructure. In this work, a multiphase-field lattice-Boltzmann method is employed to investigate the effect of thermal shock on eutectic evolution by imposing a laser spot inside the melt. Two morphology feature parameters, average growth velocity and average characteristic path deviation angle of the marginal lamellae, are introduced to quantify the out-of-equilibrium eutectic growth. A multilinear correlation between the feature parameters and the technical factors including laser power, spot radius, cooling rate, and thermal diffusivity capacity is summarized by multiple linear regression analysis. The presence of laser spot bends the solidification front by changing local temperature distribution. The local high-temperature region near the laser spot corresponds to a lower driving force and thus the depression of the solid-liquid interface. Extension to a more general model which can handle large undercooling and phase decomposition is also discussed. The laser shock, static or moving, can be regarded as an efficient tool to obtain the engineered patterns such as curved solidification front or tilt domain.