Columnar grain growth with shear flow in molten pool of Ni-Cr alloy was simulated with a coupled model of grain growth and solute transport.The results indicate that shear flow alters solute distribution at the vicinity of columnar grains.The solute concentration gradient on the upstream side is greater,while that on the downstream side is smaller,leading to asymmetrical growth of columnar grains.In the interior of a columnar grain,solute concentration increases from the bottom to the dendrite tip,but the rate of increase tends to be reduced.The simulated results are consistent with the experiments.
Three-dimensional finite element model was established to simulate temperature fields of T-joint titanium sheets during TIG welding with finite element method (FEM) software. Temperature dependent material properties and the effect of latent heat were considered. A technique of element birth and death was used to simulate the process of welded metal filling. Dynamic variation process of temperature fields during TIG welding was achieved. The simulated results agreed well with the measured results.
