Correlations of Microstructure and TEM Observations of Plasticity in Metallic Nanolaminates
D E. Kramer, Timothy J. Foecke
Nanolaminate materials exhibit increases in hardness and yield strength beyond those expected according to rule of mixtures calculations. Several models have been proposed to explain this enhancement of strength, but conclusive experimental verification is hindered by the complex interaction between ingrown defects, in-plane microstructure and compositional modulation. In this study, mechanisms of plastic deformation in nanolaminates are investigated by in situ TEM straining of epitaxial Cu/Ni nanolaminates grown on Cu (001) single crystal substrates. Two distinct types of deformation are observed. Initial plastic deformation is accommodated by motion of Orowan and threading dislocations in a uniform and random fashion. As the stress levels increase, the strength of the Cu/Ni interface is exceeded and localization of deformation occurs. Subsequent observations suggest that the intense plastic occurs over many bilayers in the direction of crack growth, but is contained to with one or two bilayer in a direction normal to the crack faces.
copper, deformation, nanolaminate, nickel, TEM
and Foecke, T.
Correlations of Microstructure and TEM Observations of Plasticity in Metallic Nanolaminates, Conference Proceedings
(Accessed December 1, 2023)