A numerical investigation of directional binary alloy solidification processes is presented. In particular, a mathematical model is developed to study macrosegregation patterns as a consequence of thermal-solutal convection in the melt and mushy zone. A good understanding of the basic mechanisms of macrosegregation is helpful in designing and controlling solidification processes in order to ach...

Solidification of materials to near net shape is one of the most commonly used and economical methods of manufacturing. Different industries impose different restrictions and design objectives on the solidification process. For example, single crystal growth requires a planar growth front whereas casting requires homogenous material distribution. There are various techniques to control the flow...

During rapid solidification, solute may be incorporated into the solid phase at a concentration significantly different from that predicted by equilibrium thermodynamics. This process, known as solute trapping, leads to a progressive reduction in the concentration change across the interface as the solidification rate increases. Theoretical treatments of rapid solidification using traditional s...

The directional solidification of the transparent binary alloy succinonitrile-poly(ethylene oxide) was studied in an experiment in which solidification speeds of about 2 mm/sec could be reached without loss of the linear temperature gradient. The low diffusivity of the polymer solute allowed the study of the dynamics of rapid solidification using an optical microscope. For both normal and doubl...

Crystallization of polymeric materials is a solidification process in strong interaction with heat conduction. Both of the basic mechanisms involved in the solidification from a melt, namely the nucleation and growth of crystals, are strongly influenced by the temperature and its variation. Vice versa, the latent heat is rather large for polymeric materials, so that it causes a considerable cha...

As with the consolidation time, the cooling rate applied during the solidification stage of the composite processing cycle influences the total processing cycle time, as well as the mechanical performance. By controlling the solidification rate, changes in the matrix morphology and crystallinity can be achieved, and hence different mechanical properties may be obtained. Control of the solidific...

This paper presents an eddy-current-based technique for imaging the solidification of molten metal inside a metal pipe. This technique is motivated by the fact that the ac (alternating current) impedance seen from a solenoid placed outside the pipe is dependent on the distribution of the solidification inside the pipe provided that the ac frequency is properly chosen and the overall thickness o...

The optimal design of risers for castings has been the subject of numerous investigations and this paper determines the optimal dimensions when Chvorinov’s rule for solidification is obeyed by both the riser and casting and solidification time is the only constraint involved .This problem can be formulated to minimize the riser volume subject to the constraint that the riser solidification time...

The present paper evaluates the effect of the nozzle characteristics on the heat transfer and phase change of the low carbon steel during the continuous casting process. A three-dimensional energy equation and a solidification model are used to drive the governing equation of the phase change and temperature distribution. A linear relation is obtained to predict the temperature-dependent of the...