Influence of growth rate on microstructure, microhardness, and electrical resistivity of directionally solidified Al-7 wt% Ni hypo-eutectic alloy

Sn–Cd eutectic melt was first obtained in a hot filling furnace and then 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 (λ) were measured from both transverse and longitudinal sections of the samples. The influence of the growth rate (V) on lamellar spacings (λ) and undercoolings (∆T) was analyzed. λ2V, ∆Tλ and ∆TV −0.5 values were determined by using λ,∆T and V values. Microindentation hardness (HV) was measured from both transverse and longitudinal sections of the specimens. HV values increase with the increasing values of V but decrease with increasing λ values. λ−V, λ−∆T and λ2V results have been compared with the Jackson–Hunt eutectic model and similar experimental results, HV −V and HV −λ results were also compared with the previous work