Different compositions of Al-Cu alloys were directionally solidified upward with constant growth rate (V congruent to 18.6 mu m s(-1)) and constant temperature gradient (G congruent to 4.7 K mm(-1)) using a Bridgman type growth apparatus. The variations in electrical resistivity rho with temperature for directionally solidified Al-Cu alloys were measured in the range of 3732773 K using a standard four-point probe technique. According to the present experimental results, the resistivity of directionally solidified Al-Cu alloys linearly increases with increasing temperature and composition of Cu in the Al-Cu alloys. The variations in Lorenz number with the temperature and composition of Cu in the Al-Cu alloys were also determined from the Wiedemann-Franz law using the measured values of thermal and electrical conductivities for the same alloys.
Pb(100x)-Snx solders (x = 5 wt.%, 10 wt.%, 20 wt.%, 35 wt.%, 50 wt.%, 60 wt.%, 61.9 wt.%, and 95 wt.%) were directionally solidified upward with a constant growth rate (V = 37.4 lm/s) in a temperature gradient (G = 4.8 K/mm) in a Bridgman-type growth apparatus. The variations of electrical resistivity (q) with temperature in the range of 323 K to 423 K for the directionally solidified Pb-Sn solders were measured. The present measurements indicate that the electrical resistivity of the directionally solidified Pb-Sn solders increases with
increasing temperature, whereas the resistivity of the Pb-Sn solders decreases with increasing Sn content. The dependency of the Lorenz number (L) on temperature and Sn content for the Pb-Sn solders was also investigated based on the Wiedemann–Franz law by using the measured values of the thermal (K) and electrical (r) conductivity for the same alloys.
