Title

The Role of Metallic Bonding in the Crystallographic Pitting of Magnesium

Document Type

Article

Publication Date

Fall 2006

Abstract

The role of metallic bonding in the crystallographic pitting of magnesium (Mg) has been investigated using atomistic simulations. To assess the degree of metallic bonding in Mg (0001) and (101¯0) surfaces the modified embedded atom method (MEAM) has been used. The interatomic potentials developed with MEAM were then used by a Monte Carlo code, standard Metropolis algorithm, to calculate atom removal probabilities. Simulations for the Mg (101¯0) surface found that atom removal formed geometric surface structures, the orientation of which were always at a 58° or 116° angle with respect to the [1¯21¯0] direction or 90° with respect to [0001]. These results are identical to published experimental results from Mg (101¯0) single crystals. Simulations of Mg (0001) surfaces found no preferred orientations similar to experimental results. Finally, the threshold potential for atom removal in our simulations follows the same trend as the critical electrochemical potential for pitting in single-crystal Mg surfaces. This result indicates that experimental differences in the pitting potential for Mg as a function of crystallographic orientation are related to the metallic bond strength (chemical potential) associated with each surface orientation.

Volume

153

Issue

9

First Page

358

Last Page

364

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