Vertically twinned aluminum nano-pillars under tensile loading: a molecular dynamics study

MM Rahman and N Sakib and AKM Ashikuzzaman and F Alam, MATERIALS RESEARCH EXPRESS, 6, 1250b4 (2019).

DOI: 10.1088/2053-1591/ab61bb

Nano twinned FCC materials show superior properties comparatively to their single crystal counterparts. The properties of nano-twinned materials are possessed by the interactions of dislocations with the coherent twin boundaries (TBs). In this paper, we describe the fabrication of arrays of vertically aligned aluminum nano-pillars that contain different number of TBs (different twin boundary spacing) and no grain boundaries or other microstructural features. We have investigated the influence of twin boundary (TB) spacing on the mechanical responses of individual nano-pillars under tensile loading. The investigation fabricated with molecular dynamics (MD) simulation reveals that, the yield strength is dependent on number of vertical twins. Yield strength increases with increasing number of twins upto a critical value and then starts to decrease with further increment of twin numbers. An increase of ductility was also found as a result of immobilized dislocation. The deformation process was nucleated by spontaneous dislocation buds and eventually turned into mature partial dislocations. The simulation was done until fracture to give an insight about dislocation behavior.

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