Early Precipitate Morphologies in Mg-Nd-(Zr) Alloys

Emmanuelle Marquis

Ellen LS Solomon, Vicente Araullo-Peters, John E Allison, and Emmanuelle A Marquis (2017)


Aging of Mg-Nd alloys involves the formation of Guinier-Preston zones followed by beta''' precipitation that is associated with peak hardness. Using atom probe tomography and high-angle annular dark-field scanning transmission electron microscopy, the three-dimensional morphologies of the coherent Guinier-Preston zones and beta''' precipitates were quantified. The Guinier-Preston zones form equiaxed plates while the beta''' precipitates are elongated along the [0001](Mg) direction thereby minimizing elastic strains. The beta''' precipitates exhibit additional faceting along the [0001](Mg) direction and along the < 1 (1) over bar 01 >(Mg) and < 1 (1) over bar 02 >(Mg) directions when viewed along the < 11 (2) over bar0 >(Mg) zone axes, which can be affected by strain field interactions from nearby precipitates. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

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