Formation and Stabilization of 18R Long-Period Stacking Order Phase Through Friction Stir Processing of Mg-Gd-Y-Zn Alloy

The present work deals with the formation and stabilization of the 18R lamellar long-period stacking order phase (LPSO) through friction stir processing of a GWZ magnesium alloy. In this regard, the formation sequence was investigated in detail, where the metastable LPSO structures were formed in the matrix and then transformed into the 18R structure. The involved micro-mechanism is also discussed with emphasis on the formation of a GP-like zone using high-resolution transmission electron microscopy.