Transformation of long-period stacking ordered structures in Mg-Gd-Y-Zn alloys upon synergistic characterization of first-principles calculation and experiment and its effects on mechanical properties

•Evolution law of long-period stacking ordered phase (LPSO) in Mg-Gd-Y-Zn alloy and its effect on mechanical properties were investigated.•First-principles calculations for 14H and 18R LPSO phases regarding thermodynamic and mechanical properties were carried out.•Superlattice structure of the LPSO phase folds the fermi surface of the brillouin zone, resulting in an increase in the elastic modulus of the LPSO phase.•Long-range interactions caused by the LPSO phase play a crucial role in suppressing dislocation motion.