Dislocation climb mediated Coble-type grain boundary deformation in gold nanocrystals

Abstract

Deformation of nanocrystalline materials often involves the grain boundary (GB) dominated creep process. However, the atomistic mechanism of diffusional mass transport along GB remains unclear. Here, we presented a mechanism of stress-driven diffusional climb of GB dislocations in gold (Au) nanocrystals by in-situ nanomechanical testing. Successive proceeding of GB dislocation climb enhances the mass transport along GBs and contributes to a Coble-type GB deformation at room temperature. These findings provide insights into the GB-dominated diffusional plasticity in nanocrystalline materials and are of significance for the creep deformation of nanocrystalline materials.

Keywords

• Grain boundary diffusional deformation
• grain boundary dislocation
• dislocation climb
• ultrahigh stress
• nanocrystalline