Experimental study of particle incorporation during dendritic solidification

The attainable undercooling and the solidification microstructures of sever al combinations of liquid Cu and liquid Ni with different nonmetallic parti cle dispersions have been studied with respect to the process of particle i ncorporation. The interaction between the particles and an advancing smooth solidification front is theoretically described by several models, which c onsider different materials parameters of the liquid and the dispersoids. T he results show that some of the model predictions qualitatively hold also for the case of a dendritic solidification front - as present during the so lidification process of an undercooled liquid. However the critical velocit ies for particle engulfment are more than three orders of magnitude larger than predicted by the current models. Moreover, the results indicate that t he morphology of the solid/liquid interface and its dependence on undercool ing are crucial parameters for the different interaction modes which are no t included in the theoretical models for the incorporation process. (C) 200 0 Elsevier Science S.A. All rights reserved.