In Situ TEM Observations of Fracture in Nanolaminated Metallic Thin Films
Timothy J. Foecke, D E. Kramer
Fracture of single crystal nanolaminted thin films has been investigated through in situ straining of cross-sectional samples of Cu/Ni nanolaminates grown on Cu (001) single crystal substrates. The earliest stages of deformation exhibits a confined layer slip mechanism. With continued straining, unstable fracture occurs creating a mixed-mode crack that propagates across the nanolaminate, roughly perpendicular to the interfaces. Eventually, stable crack growth with intense plastic deformation ahead of the crack tip occurs over many bilayers in the direction of crack growth. Simultaneously, plasticity was seen to spread only 1 or 2 bilayer distances normal to the crack, creating an extremely localized plastic zone. Transmission electron microscopic (TEM) examination after the test did not reveal the presence of dislocations in the crack wake, except where severe crack deflection was observed. By comparison, the plastic zone size in the substrate was greater by several of orders of magnitude.
International Journal of Fracture
Cu/Ni, dislocation, nanolaminate, nanolayered
and Kramer, D.
In Situ TEM Observations of Fracture in Nanolaminated Metallic Thin Films, International Journal of Fracture
(Accessed June 7, 2023)