Effect of irradiation damage on the shear strength of Cu-Nb interfaces

The influence of irradiation-induced damage on the interfacial shear strength of Cu-Nb interfaces was characterized via compression of nanolaminate pillars performed in situ in a transmission electron microscope. Chemical mixing and interfacial roughening during MeV Kr ion irradiation leads to increased interfacial shear strength by as much as 60%, from 0.6 GPa for the as-deposited material to 0.95 GPa for samples irradiated at liquid nitrogen temperature. The increase in interfacial shear strength was most pronounced at low temperatures (similar to-196 degrees C), but it is still significant at similar to 300 degrees C. This observation was correlated with increased chemical mixing at lower temperatures, as determined from compositional profiles characterized by energy-dispersive spectroscopy. (C) 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.