Determination of Thermal Conductivities of Solid and Liquid Phases for Rich-Sn Compositions of Sn-Mg Alloy

The variations of thermal conductivities of solid phases versus temperature for pure Sn and Sn-1 wt% Mg, Sn-2 wt% Mg, and Sn-6 wt% Mg binary alloys were measured with a radial heat flow apparatus. Thermal conductivity variations versus temperature for pure Sn and Sn-1 wt% Mg, Sn-2 wt% Mg, and Sn-6 wt% Mg binary alloys were found to be 60.60 +/- 3.63, 61.99 +/- 3.71, 68.29 +/- 4.09, and 82.04 +/- 4.92 W/Km, respectively. The thermal conductivity ratios of liquid phase to solid phase for pure Sn and eutectic Sn-2 wt% Mg alloy at their melting temperature were found to be 1.11 and 1.08, respectively, with a Bridgman type directional solidification apparatus. Thus the thermal conductivities of liquid phases for pure Sn and eutectic Sn-2 wt% Mg binary alloy at their melting temperature were evaluated to be 67.26 +/- 4.03 and 73.75 +/- 4.42 W/Km, respectively, by using the values of solid phase thermal conductivities and the thermal conductivity ratios of the liquid phase to the solid phase

Experimental Determination of Interfacial Energy for Solid Zn Solution in the Sn-Zn Eutectic System

The grain boundary groove shapes for Zn solid solution in equilibrium with Sn-Zn eutectic liquid were observed with a radial heat flow apparatus. From the observed grain boundary groove shapes, the Gibbs-Thomson coefficient, the solid-liquid and the grain boundary energy for the Zn solid solution in equilibrium with Sn-Zn eutectic liquid were determined to be (2.32 +/- 0.13)x10(-8) Km, (120.87 +/- 13.29)x10(-3) J.m(-2) and (194.76 +/- 23.37)x10(-3) J.m(-2), respectively. The termal conductivity of the eutectic Sn- 9 wt% Zn solid solution, kappa(S), was obtained as 74.74 W/Km by using a radial heat flow apparatus. The thermal conductivity ratio of the eutectic liquid to the eutectic solid, R = kappa(L)/kappa(S) was found to be 0.58 with a Bridgman-type directional growth apparatus. Thus, the value of the thermal conductivity of eutectic Sn-9 wt% Zn liquid solution, kappa(L), was obtained as 43.82 W/Km