Determination of Microstructure, Mechanical, Electrical and Thermal Properties of The Directionally Solidified Al-Si-Co Ternary Alloy

Abstract

In this work, Al-12.6Si-2Co (wt.%) ternary alloy of near eutectic composition was directionally solidified at a constant temperature gradient (G=7.60 K/mm) in a wide range of growth rates (V=8.35-166.30 mu m/s) using by Bridgman type growth apparatus. Flake spacing (lambda), microhardness (HV), tensile stress (sigma) and electrical resistivity (rho) were measured from directionally solidified samples. The dependence of flake spacing, microhardness, tensile stress and electrical resistivity on growth rate (V) was also determined by statistical analysis. According to these results, it has been found that for increasing values of V, the values of HV; sigma and rho increase. Variations of electrical resistivity (rho) for casting Al-Si-Co alloy were also measured at the temperature in range 300-500 K. The enthalpy of fusion (Delta H) for the Al-Si-Co alloy was determined by differential scanning calorimeter (DSC) from heating trace during the transformation from solid to liquid. The results obtained in this work were compared with the previous similar experimental results obtained for binary and ternary alloys.