RESISTIVITY OF PB AND PB-10 WT PCT SN DURING SOLIDIFICATION

The electrical resistivities of Pb and Pb-10 wt pet Sn alloy were meas ured during cooling and solidification. Three regimes corresponding to events when the metals were all liquid, liquid plus solid, and all so lid were eminent. In particular, the nucleation and growth of the soli d were captured by measuring the electrical resistivity. The resistivi ties of the liquid at the nucleation temperature of lead and of Pb-10 wt pet Sn are 94.7 and 85.7 mu Ohm cm, respectively, and nucleation in these systems occurred at 326.9 degrees C and 301 degrees C, respecti vely. In lead, it was found that the ratio of resistivity of the liqui d at the melting temperature to the resistivity of the solid was 1.92. The resistivity data were used to estimate the mass fraction of solid as a function of temperature during solidification. The method of mea suring resistivity and temperature or the models for predicting electr ical resistivity of two-phase mixtures should be improved before this method can be made quantitative.