Abstract
The present work focused on the Ni3Al-based alloy with a high melting point. The aim of the research is to study the effect of withdrawal rate on the microstructures and mechanical properties of directionally solidified Ni-25Al alloy. Ni3Al intermetallics were prepared at different withdrawal rates by directional solidification (DS) in an electromagnetic cold crucible directional solidification furnace. The DS samples contain Ni3Al and NiAl phases. The primary dendritic spacing (λ) decreases with the increasing of withdrawal rate (V), and the volume fraction of NiAl phase increases as the withdrawal rate increases. Results of tensile tests show that ductility of DS samples is enhanced with a decrease in the withdrawal rate.