Grain growth in nanocrystalline nickel films at low temperature and stress

The influence of temperature and stress on grain growth was investigated in nanocrystalline nickel thin films in situ inside a transmission electron microscope. Independently, temperature and stress did not show any appreciable effect. However, concurrent loading at only 20% of melting temperature and 20% of yield stress resulted in significant grain boundary mobility and grain growth. We propose that grain growth in nanocrystals is a stress-heterogeneity-relieving mechanism that may not necessarily be associated with plasticity as proposed in the literature.

(a) As-deposited nano-crystalline Ni (b) large grain growth at simultaneous low temperature (0.2Tm) and low stress (0.2σY) loading compared to the literature predicting grain growth around 0.4Tm and/or σY loading conditions.Figure optionsDownload high-quality image (107 K)Download as PowerPoint slide