Internal structure of the electrodeposited nanocrystalline Al-Mg alloy dendrites

摘要

Porous nanocrystalline supersaturated face centered cubic (fcc)-Al(Mg) dendrites with globular morphology were produced via electrodeposition. The cross-section of the globules revealed compact-disperse-compact structure along the growth direction. Initially compact globules formed due to high potential (or current density) which decreased eventually resulting in disperse-entity growth. Overlapping spherical diffusion zone formation over the disperse-entities was attributed as a reason for the compact growth at later stages. The internal structure of the globules was explained by the global potential (E)-time curve and the estimated local current densities ahead of deposit front. A growth mechanism for globular morphology was proposed using the results presented.