Investigations of Electrical Resistivity and Thermal Conductivity Dependences on Growth Rate in the Al–Cu–Ti Eutectic Alloy

Abstract

Directional solidification of Al–Cu–Ti (Al–33wt%Cu–0.1wt%Ti) eutectic alloy was done with a growth rate range (V = 8.58 to 2038.65 µm⋅s⁻¹) at a temperature gradient of 6.45 K⋅mm⁻¹ using Bridgman-type directional solidification furnace. The measurements of thermal conductivity (K) and electrical resistivity ($\rho$) for the Al–Cu–Ti alloy solidified with the different values of V were made by the longitudinal heat flow method (LHFM) and DC four-point probe technique (FPPT). While the highest values of K and ρ were determined to be 236.04 W⋅K^–1⋅m^–1 and 5.91 × 10⁻⁸ Ωm, respectively, at 8.58 μm⋅s^–1, the lowest values of K and ρ were obtained to be 199.82 W⋅K^–1⋅m^–1 and 12.11 × 10⁻⁸ Ωm, respectively, at 2038.65 μm⋅s^–1. The K and ρ dependences on V were obtained to be $K = 259.96\; \times \,V_{{}}^{ - 0.032}$ and $\rho = 4.47\; \times \;{10}^{{ - {8}}} \, V_{{}}^{0.13}$ from linear regression analysis. The fusion enthalpy (∆H) and specific heat difference between solid and liquid (∆C_P) for the Al–Cu–Ti were also determined to be 222.69 J⋅g^–1 and 0.266 Jg^–1⋅K^–1, respectively, by means of differential scanning calorimetry (DSC).