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Formation Formation of and interaction between beta '(F) and beta ' phases in a Mg-Gd alloy

Journal Contribution - Journal Article

© 2017 Elsevier B.V. This study reports the co-existence of β′ and β′ F phases and their interactions in an aged Mg‒Gd alloy. Observations made from high-angle annular dark-field scanning transmission electron microscopy reveal that the β′ and β′ F precipitates form linear chains along {11¯00} α and within each chain they have an alternate distribution. Four types of interfaces exist between the adjoining β′ and β′ F precipitates, and one of them is the most frequently observed. The interaction between β′ and β′ F precipitates is examined using first-principles density functional theory computations and phase field simulations. Our calculation and simulation results reveal that the β′ and β′ F phases can form simultaneously because of similar values of their formation energy. The alternate distribution can effectively reduce the magnitude of the tensile stress around, and the compressive stress in and around the β′ precipitates. One of the four types of interfaces has a more negative formation energy, and as a result, it is most frequently observed.
Journal: Journal of Alloys and Compounds
ISSN: 0925-8388
Volume: 712
Pages: 334 - 344
Number of pages: 11
Publication year:2017
Keywords:Physical chemistry, Materials science