Directional solidification and characterization of the Cd–Sn eutectic alloy

Abstract

The Cd–67.8 wt.% Sn eutectic alloy was prepared by melting together appropriate amounts of cadmium and tin (both of 99.99% purity) in a graphite crucible in a vacuum melting furnace. Then, this eutectic alloy was poured into graphite crucibles in a hot filling furnace and the samples were solidified. These samples were directionally solidified upward with different growth rate ranges (8.1–165 μm/s) at a constant temperature gradient G (4.35 K/mm) in the Bridgman type directional solidification furnace. The lamellar spacings were measured using directional solidified samples. The variations of λ with respect to V were determined by using linear regression analysis. The dependence of lamellar spacings λ on undercooling, Δ T, was also analysed. The variations of Δ T with V (at constant G) were investigated. According to these results, it has been found that with the increasing values of V, λ decreases, whereas, Δ T increases for a constant G. λ 2 V, Δ Tλ and Δ TV −0.5 values were determined by using λ, Δ T and V values. The results obtained in this work have been compared with the Jackson–Hunt eutectic theory and experimental results studied by Borland and Elliott, Clark and Elliott for the same alloy system, and also the similar alloy systems studied by Çadırlı and Gündüz, Kaya et al.