Characterization of submicrometer phase particles in rapidly solidified Mg20Nd

The rapid solidification processing technique of chill block melt spinning has led to a significant improvement in the corrosion resistance of Mg20Nd. A pseudopassivation effect is observed in melt-spun Mg20Nd ribbons due to the presence of many tessellated regions containing submicrometer-sized rod-like and ultrafine phase particles. These particles were isolated by matrix dissolution and extraction replication techniques for further study. X-ray and electron diffraction techniques revealed that the phase crystal structure was simple cubic with a = 9.1 A ̊ . Hot stage transmission electron microscopy and differential scanning calorimetry revealed that the phase was metastable up to approximately 340°C (644°F). Energy dispersive spectroscopy results on precision ion milled extraction replicas indicated that the stoichiometry of the phase was Mg 32Nd.