Effect of heat transfer between melt puddle and cooling wheel on amorphous ribbon formation

Abstract

Planar Flow melt spinning is a one step manufacturing process to produce amorphous ribbons by rapid solidification technique. Formation of amorphous structure in the ribbon highly depends on the rate of heat transfer between the melt puddle and the cooling wheel. The present study numerically analyzes the heat transfer in the melt puddle at the melt wheel contact and its influence on the amorphous structure in the end product. Space between cooling wheel and nozzle wall is taken as the computational domain initially filled with air. Flow, Energy, momentum equations along with Volume of fluid equation are employed to analyze the heat transfer and ribbon growth in the melt puddle. Geometric re-construction scheme is employed to show the melt and air boundaries in a two fluid flow domain. Numerical analysis shows a temperature gradient across the ribbon thickness. With increase in thickness the gradient is observed to increase. Experimental investigation has shown an increase in crystalline structure in the ribbon with thickness and shows a difference in XRD taken on both sides of the ribbons. The temperature gradient across the thickness of the ribbon is responsible for this phenomenon. As the model could predict this phenomenon, it can be used to predict the type of ribbon obtained at a set of process conditions prior to the experiment, thereby helps to avoid production of undesirable crystalline ribbons.