Cluster on interface of LPSO phase and matrix in Mg-Gd-Y-Ni alloy: Atomic scale insight from HAADF-STEM

Abstract

This paper reports on an atomic-scale investigation into the new rare earth element enriched clusters on the interface of long period stacking ordered (LPSO) structure and magnesium matrix in Mg-2Gd-1Y-1Ni alloy, using Cs-corrected high angle annular dark field-scanning transmission electron microscopy (HAADF-STEM). Corresponding strain mapping on the cluster was generated by GPA. Excess free volume on the interface and induced strain were applied to explain the existence of tilted arranged, periodic present clusters at the interface. The clusters, which were Gd and Ni enriched based on the EDS measurement, were periodically arranged based on the stacking sequence of LPSO structure. The strong strain field and the interaction of dislocation dipoles contributed to the tilted atomic arrangement within the cluster.