The variations of electrical resistivity and thermal conductivity with growth rate for the Zn-Al-Cu eutectic alloy

Abstract

The Zn-Al-Cu alloy (Zn-5wt%Al-0.5wt%Cu) is solidified with different growth rates (V = 8.45-2087.15 mu m s(-1)) at a constant temperature gradient (G = 3.67 K mm(-1)) using Bridgman-type directional solidification apparatus (BTDSA). The thermal conductivity (K) and electrical resistivity (rho) for the Zn-Al-Cu alloy solidified with the different V values are measured by the longitudinal heat flow method (LHFM) and DC four-point probe technique (FPPT), respectively. The lambda and K decrease with the increasing V, while the q increases with increasing V in the Zn-Al-Cu eutectic alloy. The dependences of rho and K on lambda and V for the Zn-Al-Cu eutectic alloy are obtained as rho = 9.98 x 10(-8)lambda(-0.18), q = 7.03 x 10(-8) V-0.07, K = 110.91 lambda(0.104) and K = 144.59V(-0.040), respectively. The melting enthalpy (DHf) and specific heat difference between solid and liquid phases (Delta C-p) for the Zn-Al-Cu eutectic alloy are determined as 113.89 J g(-1) and 0.172 J g(-1) K-1, respectively, by the differential scanning calorimetry (DSC).