A Monte Carlo simulation of solidification structure formation under melt shearing

Semi-solid metal (SSM) processing of alloys under applied shear has a promising future for near net-shape production of components. Although non-dendritic growth of solid is critical for semi-solid metal processing, a comprehensive understanding of morphological evolution under melt shearing is lacking. Through Monte Carlo simulation a growth-based evolution of solidification structure under different melt shearing conditions is proposed in the present work. It has been demonstrated that the nature of the diffusion boundary layer determines the growth morphology of the solid under shear. In effect, the nature of fluid flow determines the morphology of the solid by influencing the geometry of the boundary layer. A generalized explanation of morphological evolution under melt shearing is presented that qualitatively corroborates the experimental observations.