Direct observation of the grain boundaries acting as dislocation sources in nanocrystalline platinum

Previous molecular simulations and experiments suggest that grain boundaries (GBs) serve as dislocation sources in nanocrystalline metals. Although a large number of studies have been carried out, direct experimental evidence of dislocation nucleation from GBs has rarely been achieved. In this work, we performed in situ transmission electron microscopy (TEM) observations for a Pt nanocrystalline film with an average grain size of -10 nm during tensile deformation. This study revealed direct evidence of dislocation nucleation at the GBs at the atomic scale. This is different from the common hypothesis predicted by molecular dynamic simulations that only partial dislocations are emitted from GBs in small-grained structures.

Automated summary

This study used in situ TEM observations to directly reveal dislocation nucleation at grain boundaries in nanocrystalline metals. The findings contradict the common hypothesis predicted by molecular dynamic simulations, showing that complete dislocations can be emitted from grain boundaries in small-grained structures.