Dependence of electrical resistivity on temperature and composition of Al–Cu alloys

Different compositions of Al–Cu alloys were directionally solidified upward with constant growth rate (V>18?6 mm s) and constant temperature gradient (G>4?7 K mm) using a Bridgman type growth apparatus. The variations in electrical resistivity r 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.