Thermophysical Properties of Directionally Solidified the Zn-Mg Eutectic Alloy and the Effect of Growth Rates on Electrical Properties

Abstract

The study aimed to investigate the effect of growth rates (V) on the electrical properties of a Zn–3.0 Mg–2.5 Al (wt.%) eutectic alloy. The alloy was directionally solidified at four different growth rates ranging from 8.28 to 164.12 μm/s. Directional solidification experiments were conducted using a Bridgman-type solidification furnace, which was employed for controlled solidification and minimizing undesirable casting defects, following the alloy's production and casting process. The electrical resistivity (ρ) of the samples, measured using the Four-Point Probe Method (FPPM) available in the laboratory, exhibited an increasing trend ranging from 72.80 to 96.20 (nΩm) with rising growth rates. In other words, the electrical conductivity of the Zn–Mg–Al eutectic alloy varies inversely with the growth rate. Additionally, the thermophysical properties of the eutectic alloy in the casting phase were determined using differential scanning calorimetry (DSC): ΔHf (the fusion enthalpy), ΔCp (the specific heat) and TM (the melting point) (26.69 J/g, 0.043 J/gK, 618.92 K, respectively). The results obtained for the Zn–Mg–Al eutectic alloy reveal that, when compared to Zn-Al-based alloys produced under similar experimental conditions, the elements comprising the alloy and mass proportions lead to microstructural changes, which in turn affect its electrical conductivity.