The strength of the coupling between macroscopic heat flow and equiaxed grain formation in castings

Abstract

The strength of the coupling between heat flow and microstructure formation during solidification depends on the kinetics of the microstructural phenomenon. Strong coupling makes it necessary to solve the equations governing heat flow and those governing microstructure formation simultaneously in order to predict the evolution of temperature field and the microstructure. If the coupling is weak, uncoupling the equations to some extent and simplifying the calculation procedure does not affect the predictions of the calculations. In this work the strength of the coupling in the case of equiaxed eutectic grain formation is investigated in order to see to what extent the governing equations can be uncoupled. It is found that the coupling is so strong that full coupling of the equations is essential to get reliable results.