A novel strengthening mechanism in crystalline/amorphous dual-phase Mg alloys: A molecular dynamics study

The crystalline/amorphous dual-phase structure is a novel and advanced strategy to improve the mechanical properties of Mg alloys. Here, molecular dynamics simulation is employed to investigate the effect of the amorphous nanopillar size and the content of rare earth element Y on the interaction mechanism between prismatic 〈a〉 dislocation and amorphous nanopillar in the Mg alloys. The results show that the strengthening effect of amorphous nanopillar on the Mg alloys is significantly dependent on the size of the amorphous nanopillar. It is worth noting that an unconventional mechanism caused by extended dislocations appears when dislocation interacts with amorphous nanopillar, which is different from the traditional shear mechanism and Orowan mechanism of the interaction between dislocation and crystalline precipitates. The results also indicate that Y atoms can increase the difficulty of the 〈a〉 basal slip, thus preventing the perfect prismatic dislocation from decomposing into extended dislocation on basal plane.