Experimental verification of a model on melting and resolidification in a temperature gradient

The mushy zone dynamics in a temperature gradient is studied for Al–Cu alloys by comparing results of a recently published model with experimental data. Local mean composition and solid fraction in the temperature gradient are calculated as a function of time, experiments are presented for annealing times of 300 and 600 s. Despite the complexity of the numerous processes in the mushy zone, the model describing diffusion and change of solid fraction yields reasonably good agreement. The fastest dynamics of the mushy zone occurs at locations with a high gradient of solid fraction.

► Resolidification process of a mushy zone in a temperature gradient is characterized.
► The concentration distribution along the former mush is measured and calculated.
► Observing intermediate states gives insight into the mushy zone dynamics.
► Semi-quantitative agreement between model and experiment is found.
► Simulation calculations for the mushy zone dynamic are verified for the first time.