Simulation of primary dendrite competitive growth and solute concentration distribution in directional solidification DZ125 superalloy

Primary dendritic competitive growth and solute concentration distribution in directional solidification DZ125 superalloy were simulated by cellular automaton coupled with finite differential method (CA-FD) in case of a fixed temperature gradient. The results indicate that the modeling can visualize the mi-crostructural evolution of DZ125 superalloy. A solute concentration gradient of 1 % /mm from the bottom to the tip in solidified dendrite exists in mushy zone at the growth rate of 10 μm/s, meanwhile, the liquid solute concentration is decreased from 44. 16% at the interface to 38. 68% out of the solute diffusion layer. At the growth rate of 100 μm/s, the solute concentration gradient in solidified dendrites becomes smaller, compared with that of ones at 10 μm/s, and its interface liquid concentration makes 51. 54% , which is the higher than that of 10 μm/s. The liquid concentration in the dendrites is decreased from the bottom to the top as 20%/mm in mushy zone at 100μm/s, which is well in agreement with that from theoretical analysis' s.