Investigation of Microstructure, Physical and Thermal Properties of Al-Si-Sb Ternary Alloy

Abstract

Al-12.6wt. %Si-2wt. %Sb alloy was directionally solidified with different growth rates (8,33-165,45 mm/s) at a constant temperature gradient of 8,04 K/mm using by Bridgman type growth apparatus. The values of interflake spacing (l) was measured from transverse sections of the samples. The dependence of interflake spacing on the growth rate (V) was measured. Measurements of microhardness (HV), ultimate tensile strength (s) and electrical resistivity (r) of the directionally solidified samples were carried out. The dependence of microhardness, ultimate tensile strength and electrical resistivity on growth rate (V) and interflake spacing (l) was also analyzed. According to these results, it has been found that, for increasing values of V, the values of HV, s and r are increase, for increasing values of l, but values of HV, s and r are descrease.  Variations of electrical resistivity (r) for casting Al-Si-Sb alloy were also measured at the temperature in range 300-450 K. The enthalpy of fusion (DH) and specific heat (C_p) are calculated to be 282.60 J/g and 0.326 J/(g.K), respectively by means of differential scanning calorimeter (DSC) from heating trace during the transformation from liquid to solid. The results obtained in this work were compared with the similar experimental results in the literature.

Keywords: Al-Si-Sb alloy; Microstructures, Microhardness, Tensile Stress, Electrical resistivity, Enthalpy; Specific heat.