AN ANALYSIS OF THE HEAT AND MOMENTUM-TRANSFER DURING RAPID QUENCHING OF SOME MICROCRYSTALLINE MATERIALS FROM THE MELT

The process of crystalline ribbon formation by the single roller technique by rapid quenching from the melt has been studied with the aid of boundary layer theory. An easy calculation method has been proposed for the solution of heat and momentum transfer equations for the case in which the melt is rapidly quenched on to a substrate. The proposed method takes into account the viscosity change due to the temperature reduction, the heat resistance of the puddle-substrate area and the latent heat of fusion separation on the liquid-solid phase interface. The thicknesses of the ribbon calculated with the aid of the proposed method show good correlation with the experimental results. The quenching rates within the volume of the puddle for Al-Cu eutectic alloy are considered. © 1990 Chapman and Hall Ltd.