Application of In Situ TEM to Investigate Irradiation Creep in Nanocrystalline Zirconium

This work characterizes the irradiation creep response of nanocrystalline zirconium by nanoscale quantitative tensile loading and ion irradiation experiments performed simultaneously in situ inside a transmission electron microscope. Microfabricated devices consisting of a freestanding Zr tensile specimen 100 nm in thickness on an elastic Si test frame were produced, and subsequent ex situ ion irradiations were performed on devices with 1.4 MeV Zr ions to a nominal damage level of 0.26 displacement per atom. Subsequent in situ creep experiments performed with and without 1.4 MeV Zr ion irradiation at different applied tensile loads revealed that creep rates were enhanced by the simultaneous radiation damage. This coupled in situ nanomechanical and irradiation methodology enables rapid quantification of both the irradiation creep compliance and associated microstructural evolution.