Transition from Cell/Dendrite to Stable Interface-Morphology and Characteristic Dimensions

The cell/dendrite to absolute stable transition of solid/liquid interface is investigated on the dilute copper aluminum alloy. Surface grazing by YAG laser at high scanning rate is used for the alloy. The solidified microstructure is observed by using the scanning election microscope (SEM). The solidification rate and the temperature gradient are estimated by the finite element program, which performs for the thermal conduction analysis. The interface has changed its morphology from cell to planer interface at the transition with increasing in growth rate. Near the absolutely stable growth rate, the primary arm spacing decreases with the increase of solute concentration. The observed primary arm spacing is compared with those predicted by theory for cellular growth.