Microstructure and solidification behavior of cast GaInSb alloys

GaInSb concentrated solid solutions have been prepared using the casting configuration of the vertical feeding method (VFM). The solute microscopic distributions studied by means of back-scattered electron imaging and EDAX microprobe are detailed. Results show that with the low casting (LC) configuration the materials are almost homogenous with an average In concentration lower than the nominal one and show an inverted longitudinal solute segregation profile in comparison with classical techniques. While in the high casting (HC) configuration, the materials exhibit a microscopic compositional distribution with an average In concentration close to the nominal one. With regard to quenching and previous VFM experiments, the difference of In spatial distribution observed in LC and HC experiments is attributed to different heat extraction regimes.