Tracing the growth rate changes during vertical directional solidification by electrical resistance measurements

Abstract

Abstract At a constant alloy composition, the properties of directionally solidified material depend strongly on the evolution of its microstructure affected by the variation of growth rate V and the temperature gradient G in the vicinity of the solidification front. Several research groups are currently attempting to improve the directional solidification process with mathematical modeling and/or development of a sensor technology for in-situ monitoring of crucial solidification parameters during the process. In this paper the applicability and efficiency of the combined in-situ electrical resistance and temperature measurements for characterization of directional solidification of the eutectic Sn–Pb alloy is presented. Sensor technology shown in this paper exploits the large differences in the electrical resistivity of solid and liquid phases for determination of the current position X(t) and growth rate V(t) of the solidification front.