Coupled Simulation on Temperature Field and Microstructure Formation Process of K4169 Superalloy Blade in Investment Casting
In order to control the grain structure of K4169 superalloy blade which affects its mechanical performance and ability of resistance to corroding in high temperature state, the transient temperature field distributions were analyzed by using equivalent thermal entropy method with the consideration of the practical boundary conditions, such as, heat exchange and heat radiation in solidification, and the relationships between temperature and time of every point on vertical section and cross section during phase change heat transference process of K4169 superalloy were obtained. The changes of solid phase fraction after every time step were calculated basing on the model of equiaxed dendrite growth solute diffusion put forward by Rappaz and other persons. we used the data to modify the temperature in the same step when phase change latent heat was released. The Cell Automaton technology was adopted to coupled simulate the grain structure formation process of K4169 superalloy blade with its temperature fields using continuous nucleation model and kinetic model of dendrite tip growth. These simulation results which coincided much well with the ones of experiment test have played a very important role in studying superalloy mechanical performance and ability of resistance to corroding of K4169 alloy blades.