A Novel Fe-enriched Lamella Sandwich Precipitate Formed in A Mg-Gd-Fe Alloy

【摘要】 A novel Fe-enriched lamella sandwich phase （χ-phase） has been found to precipitate along the basal （0001）_Mg planes in the heat-treated Mg-Gd-Fe alloy and its structure is clearly revealed by means of atomic-resolution transmission electron microscopy.The layered χ-phase only has a thickness of mono-unit-cell and consists invariably of ten atomic layers stacking along the[0001]_Mg direction,of which the outermost atomic layers had larger in-plane atom-pillar spacing than the inner layers.Fe/Gd atoms are mainly enriched in the outer four atomic layers in the χ-phase,forming two structurally unsymmetrical four-layer shells to sandwich the middle two Mg layers.An atomic model has been proposed for this layered sandwich-structured χ-phase.更多还原

【Abstract】 A novel Fe-enriched lamella sandwich phase （χ-phase） has been found to precipitate along the basal （0001）_Mg planes in the heat-treated Mg-Gd-Fe alloy and its structure is clearly revealed by means of atomic-resolution transmission electron microscopy.The layered χ-phase only has a thickness of mono-unit-cell and consists invariably of ten atomic layers stacking along the[0001]_Mg direction,of which the outermost atomic layers had larger in-plane atom-pillar spacing than the inner layers.Fe/Gd atoms are mainly enriched in the outer four atomic layers in the χ-phase,forming two structurally unsymmetrical four-layer shells to sandwich the middle two Mg layers.An atomic model has been proposed for this layered sandwich-structured χ-phase.更多还原