Molecular dynamics simulation of mechanism of interaction between dislocation and amorphism in magnesium

BJ Zhang and MR An and T Hu and L Han, ACTA PHYSICA SINICA, 71, 143101 (2022).

DOI: 10.7498/aps.71.20212318

As the lightest metal structural material, magnesium alloy is known as the "green engineering material" ofthe 21st century. Especially, crystalline-amorphous dual-phase nanostructure magnesium materials exhibitexcellent mechanical properties, though the mechanism of interaction between the dislocation in crystal andamorphous phase is still under the investigation. In the present work, the interaction between the edgedislocation and amorphous phase in nanocrystalline magnesium under shear load is studied by using moleculardynamics simulation. The result indicates that the interaction mechanism between amorphous phase anddislocation shows the size dependence. Compared with the sample with smaller amorphous size, largeramorphous size will lead to a large second strengthening effect. And the mechanism of the interaction betweenamorphous phase and dislocation is mainly attributed to the pinning effect of amorphous on the dislocation. Forthe samples with small amorphous size, the pinning effect of amorphous on the dislocation is limited and thepinning time is shorter. The interaction mechanism is contributed mainly by the dislocation bypassingamorphous phase. While for the samples with larger amorphous size, the pinning effect of amorphous on thedislocation is larger and the pinning time is longer. The interaction is due mainly to the cross slip mechanism ofdislocation caused by amorphous phase. The results from this work have a certain reference value and guidingsignificance for designing and preparing the high-performance magnesium and its alloya

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