Applying fluxing method, hypercooling was achieved in Co80Pd20 alloys. The rapidly solidified microstructures and substructures of hypercooled Co80Pd20 alloys, subjected to rapid quenching and natural cooling after recalescence, have been studied. Transmission electron microscopy was used to investigate the substructures such as dislocations in the as solidified microstructures. X-ray diffraction line profile analysis was used for illuminating and determining the microstrain due to rapid solidification in the as solidified microstructures. In the undercooling range studied, the microstrain in the rapidly solidified structures increases with increasing undercooling. Quenching immediately after rapid solidification is helpful to preserving the microstrain in the microstructures.