Jiangwei Wang¹, Qi Zhu¹, Siyuan Wei¹, Chuang Deng², Scott X. Mao³, Frederic Sansoz⁴; ¹Zhejiang University, ²The University of Manitoba, ³University of Pittsburgh, ⁴The University of Vermont

Interfaces, including grain boundaries (GB s), twin boundaries (TBs) and interphase boundaries, critically influence the mechanical properties and deformation mechanisms in metals and alloys. In this talk, I will present our recent progresses on the atomistic mechanisms governing the interface-dominated plasticity in metallic nanostructured materials, using the in situ nanomechanical testing. We revealed that the grain boundaries can migrate reversibly in shear loading cycles through a disconnection-mediated mechanism, in which the nucleation, lateral propagation and dynamic interactions of different types of GB disconnections control the deformation; the dislocation-twin interactions in nanotwinned metallic materials are strongly influenced by the twin size, where the dislocation slip on the uncommon (001) planes can be effectively activated with the twin size decreases；while in metallic nanolamellar materials, the interface structures strongly influence the deformation and crack formation. These findings provide novel insights into the interface-dominated plasticity in a broad class of metallic materials.