Internal structure of the electrodeposited nanocrystalline Al–Mg alloy dendrites

Abstract

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.