Measurements of electrical and thermal properties with growth rate, alloying elements and temperature in the Al-Si-X alloys

In this work, effect of alloying elements (X = Cu, Co, Ni, Sb and Bi) and growth rates on the microstructure, physical properties (electrical resistivity, enthalpy and specific heat) of the directionally solidified Al-Si eutectic alloy have been investigated. Al-12.6Si-2X (wt. %) samples were prepared using metals of 99.99% high purity in the vacuum atmosphere. These alloys were directionally solidified under constant temperature gradient, G (7.80K/mm) and different growth rates, V (8.3-166.0 mu m/s). Flake spacing (lambda) and electrical resistivity (rho) were measured from the solidified samples. The variation of electrical resistivity with temperature in the range of 300-500K for alloying elements in the Al-Si eutectic cast alloy was also measured. The enthalpy of fusion (Delta H) and specific heat (C-p) for the same alloy were determined by a differential scanning calorimeter from the heating curve during the transformation from solid to liquid.