Banded structure of the electrodeposited nanocrystalline Al-Mg alloy dendrites

摘要

Nanocrystalline Al-Mg dendrites with smooth (face centered cubic (fcc)-Al(Mg)) and rough (hexagonal close packed (hcp)-Mg(Al)) globular morphology were electrodeposited. The longitudinal sections of the rough globules exhibited bright-dark banded structure possessing Mg-poor and Mg-rich compositions respectively. The banded structure was explained by considering the fluctuations in potential(E)-time curve. More negative potentials result in Mg-rich dark bands. Mg-poor bright bands appear at less negative potentials. A mechanism was proposed for the banded structure formation in Al-Mg dendrites.