1993 Volume 33 Issue 9 Pages 941-948
A numerical program has been developed in order to calculate the time-dependent thermal gradient and isotherm velocity within a solidifying pool obtained by stationary laser treatment. The heat diffusion equation is solved for an axisymmetric geometry with an enthalpy formulation using a standard FDM implicit scheme. The program has been used to investigate to which extent the cellular dendritic growth orientation is affected by the direction and amplitude of the thermal gradient.
Experiments were carried out on Al-1 mass%Si dendritic single crystals oriented by Laue back reflection technique and cut along precise crystallographic orientations prior to laser irradiation and on Al-3 mass%Cu eutectic polycrystalline alloys. Deviation of cellular dendritic growth direction from crystallographic and heat flux directions are reported. In addition, the comparison of the microstructural spacings with theoretical predictions outlines the influence of crystallography on the microstructural development during stationary laser treatment.
