Abstract
We investigated the solidification behavior in heavy rare earth based alloys by gas jet type levitation method. This method has good advantage for getting amorphous and metastable phases. Containerless process provides undercooling; hence the nucleation and crystal growth analysis can be possible during solidification. In general, Laves phases form more dominantly in the rare earth-transition metal alloys, thus, it is quite difficult to achieve the undercooled state. In this study, spherical Gd65Fe10Co10Al15 and Gd65Fe10Co10Ag5Al10 samples with a diameter of 5.5 mm were successfully solidified through high undercooling. XRD patterns confirmed the presence of Laves phases and the intensities were decreased as the cooling rate increased. Along with this result, the change in microstructure of the solidified sample was also observed using SEM. The magnetization and Curie temperature of the solidified sample varied with increasing the cooling rate. Moreover, DTA result confirmed the formation of metastable phase with showing broad endothermic peaks. We have successfully achieved to find validities that the gas flow type levitation process is able to create the metastable phase, and the Laves phase revelation would be weaken by undercooling in Gd-based alloys.
