Migration kinetics of twinning disconnections in nanotwinned Cu: An in situ HRTEM deformation study

Growth or annealing twins normally form rectangular shape with abundant incoherent twin boundaries (ITBs), while deformation twins exhibit lenticular shape that composed of serrated coherent twin boundaries (SCTBs). Using in situ high-resolution TEM (HRTEM) deformation technique, here we report the formation-mechanism differences between twinning disconnection (TD) facets/serrations and ITBs. The HRTEM results of nanotwinned Cu manifested the multiple TD facets formation on CTBs by interaction of directional partial dislocations, via migration of TDs along shearing direction. In comparison, periodic 3-layered TDs or ITBs structure were normally formed by annealing or growth process that introduced by spontaneous directionless partial dislocations. (C) 2020 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

Automated summary

This study revealed the formation mechanism differences between growth/annealing twins and deformation twins through HRTEM technique, showing that the former typically form rectangular shapes with abundant incoherent twin boundaries, while the latter exhibit lenticular shapes with serrated coherent twin boundaries.