Substructure Hardening and Twinning Suppression in Graphene Oxide‐Reinforced Magnesium Nanocomposites

The AZ31 magnesium matrix nanocomposites reinforced by 0, 1.2, 2.4 vol% graphene oxide (GO) nanoplatelets are thermomechanically fabricated through friction stir processing, and the influence of nanoplatelets on slip/twin activity is discussed in detail. The addition of GO significantly adjusts the characteristics of the developed substructure during the fabrication route and improves the matrix strength and work hardening rate in further mechanical loading. The presence of GO led to an increase in the length of low‐angle boundaries and higher dislocation storage in their vicinity can be found, highlighting the hardening effect of dislocation movements and increased flow stresses. The well‐defined developed substructure suppresses extension twinning leading to a twinning‐to‐slip deformation mode transition. Along with intensifying the substructure development, GO increases total intragranular strains developed during the fabrication and causes an improvement in the nanocomposites’ overall strength.