HRTEM observation of age-precipitation in Mg-Gd-Y alloys

Precipitation in Mg-Gd-Yalloyswhich have the different total amount of REwereinvestigated by HRTEM and SAED technique, and calculation of HRTEMimagesand electron density by first principles to understand the relationship between precipitation in these alloys and HRTEM images. The diffuse scattering by SAEDwasobtained in as-quenched samples in each alloy, and mono-layer zones have been confirmed by HRTEM observation. The atomic position just consisted of the RE and Mg columns show the black contrast, and the bright dots correspond to the space surrounding by the six Mg columns of hexagonal network with 0.18 nm. This is also corresponded the distribution of electron density of the cluster according to calculation by first principles.