Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
7880262 | Acta Materialia | 2015 | 10 Pages |
Abstract
Although their mechanical behavior has been extensively studied, the atomic-scale deformation mechanisms of metallic nanowires (NWs) with growth twins are not completely understood. Using our own atomic-scale and dynamic mechanical testing techniques, bending experiments were conducted on single-crystalline and twin-structural Ni NWs (D = â¼40 nm) using a high-resolution transmission electron microscope (HRTEM). Atomic-scale and time-resolved dislocation nucleation and propagation activities were captured in situ. A large number of in situ HRTEM observations indicated strong effects from the twin thickness (TT) on dislocation type and glide system. In thick twin lamella (TT > â¼12 nm) and single-crystalline NWs, the plasticity was controlled by full dislocation nucleation. For NWs with twin thicknesses of â¼9 nm < TT < â¼12 nm, full and partial dislocation nucleation occurred from the free surface, and the dislocations glided on multiple systems and interacted with each other during plastic deformation. For NWs with twin thicknesses of â¼6 nm < TT < â¼9 nm, partial dislocation nucleation from the free surface and the gliding of those dislocations on the plane that intersected the twin boundaries (TBs) were the dominant plasticity events. For the NWs with twin thicknesses of â¼1 nm < TT < â¼6 nm, the plasticity was accommodated by a partial dislocation nucleation process and glide parallel to the TBs. When TT < â¼1 nm, TB migration and detwinning processes resulting from partial dislocation nucleation and glide adjacent to the TBs were frequently observed.
Related Topics
Physical Sciences and Engineering
Materials Science
Ceramics and Composites
Authors
Lihua Wang, Yan Lu, Deli Kong, Lirong Xiao, Xuechao Sha, Jialin Sun, Ze Zhang, Xiaodong Han,