Effects of directional solidification on hardness and microstructure in Al–3wt.%Cu–1wt.%Li alloy

Abstract

Solidification is probably one of most important phase transformations in materials manufacturing. Additionally, a wide range of solidification microstructural features is obtained depending on processing parameters. Mechanical properties of the cast are influenced by the microstructure obtained after solidification. The aim of this work is to investigate how solidification conditions affect solidification and the resulting microstructure of the Al– 3wt.%Cu–1wt.%Li (ternary system) alloy. The alloy was solidified unidirectionally upward through a water-cooled steel plate. Results include secondary dendritic arm spacing (SDAS), hardness and microstructure analysis using optical microscopy. Results showed that SDAS values tended to increase as the distance from the heat-exchange surface increased (P). Conversely, hardness decreases as P increased.