Modelling of As-Cast Structures

International audienceThe application of solidification theories to the case of the casting of aluminium alloys might be made difficult for several reasons. Firstly, depending upon the density of inoculant particles and cooling rate, the as-cast microstructure can be globular, globular-dendritic or dendritic. Therefore, the distribution of secondary eutectic phases is not always simply correlated to the secondary dendrite arm spacing but can also strongly depend upon the grain size and morphology. Secondly, the characteristic length of the microstructure (secondary dendrite arm spacing or grain size) is much finer than the scale of the cast ingots (e.g., typically meter for the Direct Chill (DC) casting process). Finally, convection effects can be very important (e.g., transport and fragmentation of grains). In the present paper, a short review of the models available for the prediction of as-cast microstructures in aluminium alloys is made. Particular emphasis is placed at the level of the grains. First attempts to include convection effects into such models are also briefly presented