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 µm 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 (ρ) 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 λ and K decrease with the increasing V, while the ρ increases with increasing V in the Zn–Al–Cu eutectic alloy. The dependences of ρ and K on λ and V for the Zn–Al–Cu eutectic alloy are obtained as $\rho = 9.98 \times {{10}}^{{ - {{8}}}} \lambda^{{ - 0.18}}$, $\rho = 7.03 \times {{10}}^{{ - {{8}}}} V_{{}}^{{0.07}}$, $K = 110.91\lambda ^{{0.104}}$ and $K = 144.59V_{{}} ^{{ - 0.040}}$, respectively. The melting enthalpy (ΔH_f) and specific heat difference between solid and liquid phases (ΔC_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).