Interactions between Dislocations and Penta-Twins in Metallic Nanocrystals

Dislocation interactions with twin boundary (TB) have been well-established in nanotwinned metals. Penta-twins, as an extreme of crystal twinning, are tacitly assumed to be more effective at blocking dislocation motions than conventional single or coplanar nanotwins. However, the mechanism underlying between dislocations and penta-twins remains largely unclear. Here, by combining situ transmission electron microscope (TEM) nanomechanical testing atomistic simulations, we rationalize fundamental Au nanocrystals. Our results reveal that show some similar behaviors ones cases nanotwins, including impedance TBs, cross-slip into twinning plane across TB. In addition, also exhibit unique during interactions, multiple cross-slip, dislocation-induced core dissociation climb-induced annihilation/absorption penta-twin core. These findings enhance our mechanistic understanding penta-twins, shedding light on accessible design high-performance nanomaterials multi-twinned nanostructures.