Directional solidification of Zn-Al-Cu eutectic alloy by the vertical Bridgman method

In the present work, the effect of growth rate and temperature gradient on microstructure and mechanical properties of Zn-7wt.%Al-4wt.%Cu eutectic alloy has been investigated. Alloys prepared under steady-state conditions by vacuumed hot filing furnace. Then, the alloys were directionally solidified upward with different growth rates (V=11.62-230.77 mu m/s) at a constant temperature gradient (G=7.17 K/mm) and with different temperature gradients (G=7.17-11.04 K/mm) at a constant growth rate (V=11.62 mu m/s) by a Bridgman furnace. The microstructures were observed to be lamellae of Zn, Al and broken lamellae CuZn4 phases from quenched samples. The values of eutectic spacing, microhardness and ultimate tensile strength of alloys were measured. The dependency of the microstructure and mechanical properties on growth rate and temperature gradient were investigated using regression analysis

Directional solidification of Zn-Al-Cu eutectic alloy by the vertical Bridgman method

In the present work, the effect of growth rate and temperature gradient on microstructure and mechanical properties of Zn-7wt.%Al-4wt.%Cu eutectic alloy has been investigated. Alloys prepared under steady-state conditions by vacuumed hot filing furnace. Then, the alloys were directionally solidified upward with different growth rates (V=11.62-230.77 mm/s) at a constant temperature gradient (G=7.17 K/mm) and with different temperature gradients (G=7.17-11.04 K/mm) at a constant growth rate (V=11.62 mm/s) by a Bridgman furnace. The microstructures were observed to be lamellae of Zn, Al and broken lamellae CuZn4 phases from quenched samples. The values of eutectic spacing, microhardness and ultimate tensile strength of alloys were measured. The dependency of the microstructure and mechanical properties on growth rate and temperature gradient were investigated using regression analysis

Measurement of Solid-Liquid Interfacial Energy for Solid Zn in Equilibrium with the ZnMg Eutectic Liquid

The equilibrated grain boundary groove shapes for solid Zn in equilibrium with the ZnMg eutectic liquid were observed on rapidly quenched samples. The Gibbs-Thomson coefficient for the solid Zn has been determined to be (10.64 +/- 0.43) x 10(-8) K m from the observed grain boundary groove shapes with the present numerical model, and the solid-liquid interfacial energy for the solid Zn in equilibrium with the ZnMg eutectic liquid has been obtained to be (89.16 +/- 8.02) x 10(-3) J m(-2) from the Gibbs-Thomson equation. The grain boundary energy for the solid Zn has also been calculated to be (172.97 +/- 20.76) x 10(-3) J m(-2) from the observed grain boundary groove shapes

The Experimental Determination of Interfacial Energies for Solid Cd in Equilibrium with Sn-Cd-Sb Liquid

The equilibrated grain boundary groove shapes of solid Cd in equilibrium with Sn-Cd-Sb liquid were observed from a quenched sample by using a radial heat flow apparatus. The Gibbs-Thomson coefficient, solid-liquid interfacial energy, and grain boundary energy of the solid Cd were determined from the observed grain boundary groove shapes. The thermal conductivity of the eutectic solid phase for Sn-35.80 at. pct Cd-6.71 at. pct Sb alloy and the thermal conductivity ratio of the liquid phase to the solid phase for Sn-35.80 at. pct Cd-6.71 at. pct Sb alloy at eutectic temperature were also measured with a radial heat flow apparatus and a Bridgman-type growth apparatus, respectively

Determination of thermo-electrical properties in Sn based alloys

The variation of thermal conductivity of solid phase versus temperature for Sn-21 wt.% Bi, Sn-25 wt.% In and Sn-35 wt.% In-26 wt.% Bi alloys were measured with a radial heat flow apparatus. From the graphs of thermal conductivity versus temperature, the thermal conductivity of the solid phases at their melting temperatures and the thermal temperature coefficients for the same alloys were obtained. The ratios of thermal conductivity of liquid phase to solid phase for the same materials were measured with a Bridgman type directional solidification apparatus. The variations of electrical conductivity of solid phases versus temperature for the same alloys were determined from the Wiedemann-Franz law by using the measured values of thermal conductivity. From the graphs of electrical conductivity versus temperature, the electrical temperature coefficients for the same alloys were also determined. According to present experimental results it can be concluded that the thermal and electrical conductivity of Sn based alloys depend on the thermal and electrical conductivity of the alloying elements. If the thermal and electrical conductivity of the alloying elements are lower than the thermal conductivity of Sn, the thermal conductivity of Sn based alloys decreases, whereas, otherwise, it increases