Presentation Dr. Eskin

Liquid metal flow and solidification of aluminium alloys
D. Eskin
The Netherlands Institute for Metals Research, Delft, The Netherlands

Flow of liquid metal is an intrinsic feature of all metallurgical processes, starting from melting and holding of melt in furnaces, through delivery of liquid metal to a casting station to the different stages of solidification. The most interesting and challenging subject of research is the interaction of this flow with solidifying material. The known effects of melt flow of the structure formation during solidification include change of dendrite morphology, deviation of grain growth direction, deformation of dendrite branches, fragmentation of dendrites as well as the transport of the solid phase on the scale of a casting and the feeding of the solid phase deep in the mushy zone. The last two phenomena may result in macrosegregation and hot tearing. Melt flows can be generally classified as natural and forced flows. The former are a result of natural causes such as temperature, solutal or other gradients (convection), or pressure drop (feeding). The latter can be imposed onto the melt by external forces, e.g. mechanical or electromagnetic stirring, or cavitation. This presentation is focused on the effect of natural and forced flows on the formation of structure and defects during casting of aluminium alloys. Practical examples are given and discussed.

11.11.05, 14:45 room 406, ILR, Marschnerstr. 32, TU Dresden